diff --git a/docs-developer/CHANGELOG-formats.md b/docs-developer/CHANGELOG-formats.md
index 918c5b23b4..7d35fa46c7 100644
--- a/docs-developer/CHANGELOG-formats.md
+++ b/docs-developer/CHANGELOG-formats.md
@@ -6,6 +6,12 @@ Note that this is not an exhaustive list. Processed profile format upgraders can
 
 ## Processed profile format
 
+### Version 52
+
+No format changes, but a front-end behavior change: The schema for a marker is now looked up purely based on its `data.type`. In the past there were some special cases when `data` was `null`, or when `data.type` was `tracing` or `Text`. These special cases have been removed. The new behavior is simpler and more predictable, and was probably what you expected anyway.
+
+This change came with a new version because we needed to upgrade old profiles from Firefox which were relying on the more complex behavior.
+
 ### Version 51
 
 Two new marker schema field format types have been added: `flow-id` and `terminating-flow-id`, with string index values (like `unique-string`).
diff --git a/src/actions/receive-profile.js b/src/actions/receive-profile.js
index af83bc8053..84ee8b7521 100644
--- a/src/actions/receive-profile.js
+++ b/src/actions/receive-profile.js
@@ -38,7 +38,6 @@ import {
   getRelevantPagesForActiveTab,
   getSymbolServerUrl,
   getActiveTabID,
-  getMarkerSchemaByName,
 } from 'firefox-profiler/selectors';
 import {
   getSelectedTab,
@@ -321,11 +320,7 @@ export function finalizeFullProfileView(
       tabFilter,
       tabToThreadIndexesMap
     );
-    const localTracksByPid = computeLocalTracksByPid(
-      profile,
-      globalTracks,
-      getMarkerSchemaByName(getState())
-    );
+    const localTracksByPid = computeLocalTracksByPid(profile, globalTracks);
 
     const legacyThreadOrder = getLegacyThreadOrder(getState());
     const globalTrackOrder = initializeGlobalTrackOrder(
@@ -1835,11 +1830,7 @@ export function changeTabFilter(tabID: TabID | null): ThunkAction<void> {
       tabID,
       tabToThreadIndexesMap
     );
-    const localTracksByPid = computeLocalTracksByPid(
-      profile,
-      globalTracks,
-      getMarkerSchemaByName(getState())
-    );
+    const localTracksByPid = computeLocalTracksByPid(profile, globalTracks);
 
     const legacyThreadOrder = getLegacyThreadOrder(getState());
     const globalTrackOrder = initializeGlobalTrackOrder(
diff --git a/src/app-logic/constants.js b/src/app-logic/constants.js
index f80c2fdad8..10b8dc0375 100644
--- a/src/app-logic/constants.js
+++ b/src/app-logic/constants.js
@@ -14,7 +14,7 @@ export const GECKO_PROFILE_VERSION = 31;
 // The current version of the "processed" profile format.
 // Please don't forget to update the processed profile format changelog in
 // `docs-developer/CHANGELOG-formats.md`.
-export const PROCESSED_PROFILE_VERSION = 51;
+export const PROCESSED_PROFILE_VERSION = 52;
 
 // The following are the margin sizes for the left and right of the timeline. Independent
 // components need to share these values.
diff --git a/src/components/tooltip/Marker.js b/src/components/tooltip/Marker.js
index 916f224037..df3797ae67 100644
--- a/src/components/tooltip/Marker.js
+++ b/src/components/tooltip/Marker.js
@@ -239,11 +239,7 @@ class MarkerTooltipContents extends React.PureComponent<Props> {
 
     if (data) {
       // Add the details for the markers based on their Marker schema.
-      const schema = getSchemaFromMarker(
-        markerSchemaByName,
-        marker.name,
-        marker.data
-      );
+      const schema = getSchemaFromMarker(markerSchemaByName, marker.data);
       if (schema) {
         for (const schemaData of schema.data) {
           // Check for a schema that is looking up and formatting a value from
diff --git a/src/profile-logic/gecko-profile-versioning.js b/src/profile-logic/gecko-profile-versioning.js
index d7f86f6d0d..9520905b59 100644
--- a/src/profile-logic/gecko-profile-versioning.js
+++ b/src/profile-logic/gecko-profile-versioning.js
@@ -1252,27 +1252,27 @@ const _upgraders = {
           // eventType is in the payload as well.
         ],
       },
+
+      // The following three schemas should have just been a single schema named
+      // "tracing". They are kept here for historical accuracy.
+      // There is a processed profile format upgrader (version 52) which adds the
+      // "tracing" schema for profiles which don't have it.
       {
-        // TODO - Note that this marker is a "tracing" marker currently.
-        // See issue #2749
         name: 'Paint',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'category', label: 'Type', format: 'string' }],
       },
       {
-        // TODO - Note that this marker is a "tracing" marker currently.
-        // See issue #2749
         name: 'Navigation',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'category', label: 'Type', format: 'string' }],
       },
       {
-        // TODO - Note that this marker is a "tracing" marker currently.
-        // See issue #2749
         name: 'Layout',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'category', label: 'Type', format: 'string' }],
       },
+
       {
         name: 'IPC',
         tooltipLabel: 'IPC — {marker.data.niceDirection}',
@@ -1288,6 +1288,14 @@ const _upgraders = {
         ],
       },
       {
+        // An unused schema for RefreshDriverTick markers.
+        // This schema is not consistent with what post-schema Firefox would
+        // output. Firefox (as of Jan 2026) is still using Text markers and does
+        // not have a RefreshDriverTick schema. Furthermore, upgraded profiles
+        // which get this schema do not have any { type: 'RefreshDriverTick' }
+        // markers - in the past they picked up this schema due to a compat hack,
+        // but this hack is now removed. So this schema is unused. It is kept
+        // here for historical accuracy.
         name: 'RefreshDriverTick',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'name', label: 'Tick Reasons', format: 'string' }],
diff --git a/src/profile-logic/marker-data.js b/src/profile-logic/marker-data.js
index fa1aa55edf..98f8278181 100644
--- a/src/profile-logic/marker-data.js
+++ b/src/profile-logic/marker-data.js
@@ -14,7 +14,6 @@ import {
   INTERVAL_END,
 } from 'firefox-profiler/app-logic/constants';
 import {
-  getMarkerSchemaName,
   getSchemaFromMarker,
   markerPayloadMatchesSearch,
 } from './marker-schema';
@@ -226,11 +225,7 @@ function positiveFilterMarker(
     }
 
     // Now check the schema for the marker payload for searchable
-    const markerSchema = getSchemaFromMarker(
-      markerSchemaByName,
-      marker.name,
-      marker.data
-    );
+    const markerSchema = getSchemaFromMarker(markerSchemaByName, marker.data);
     if (
       markerSchema &&
       markerPayloadMatchesSearch(markerSchema, marker, stringTable, test)
@@ -292,11 +287,7 @@ function negativeFilterMarker(
     }
 
     // Now check the schema for the marker payload for searchable
-    const markerSchema = getSchemaFromMarker(
-      markerSchemaByName,
-      marker.name,
-      marker.data
-    );
+    const markerSchema = getSchemaFromMarker(markerSchemaByName, marker.data);
 
     if (
       markerSchema &&
@@ -1287,14 +1278,12 @@ export function getAllowMarkersWithNoSchema(
     const { data } = marker;
 
     if (!data) {
-      // Keep the marker if there is payload.
+      // Keep the marker if there is no payload.
       return true;
     }
 
     if (!markerSchemaByName[data.type]) {
-      // Keep the marker if there is no schema. Note that this function doesn't use
-      // the getMarkerSchemaName function, as that function attempts to find a
-      // marker schema name in a very permissive manner. In the marker chart
+      // Keep the marker if there is no schema. In the marker chart
       // and marker table, most likely we want to show everything.
       return true;
     }
@@ -1528,9 +1517,8 @@ export function filterMarkerByDisplayLocation(
       return additionalResult;
     }
 
-    return markerTypes.has(
-      getMarkerSchemaName(markerSchemaByName, marker.name, marker.data)
-    );
+    const schemaName = marker.data ? (marker.data.type ?? null) : null;
+    return schemaName !== null && markerTypes.has(schemaName);
   });
 }
 
diff --git a/src/profile-logic/marker-schema.js b/src/profile-logic/marker-schema.js
index 91046ffbd6..18b17c2dec 100644
--- a/src/profile-logic/marker-schema.js
+++ b/src/profile-logic/marker-schema.js
@@ -82,56 +82,16 @@ export const markerSchemaFrontEndOnly: MarkerSchema[] = [
   },
 ];
 
-/**
- * For the most part, schema is matched up by the Payload's "type" field,
- * but for practical purposes, there are a few other options, see the
- * implementation of this function for details.
- */
-export function getMarkerSchemaName(
-  markerSchemaByName: MarkerSchemaByName,
-  markerName: string,
-  markerData: MarkerPayload | null
-): string {
-  if (!markerData) {
-    // Fall back to using the name if no payload exists.
-    return markerName;
-  }
-
-  const { type } = markerData;
-  if (type === 'tracing' && markerData.category) {
-    // TODO - Tracing markers have a duplicate "category" field.
-    // See issue #2749
-
-    // Does a marker schema for the "category" exist?
-    return markerSchemaByName[markerData.category] === undefined
-      ? // If not, default back to tracing
-        'tracing'
-      : // If so, use the category as the schema name.
-        markerData.category;
-  }
-  if (type === 'Text') {
-    // Text markers are a cheap and easy way to create markers with
-    // a category. Check for schema if it exists, if not, fallback to
-    // a Text type marker.
-    return markerSchemaByName[markerName] === undefined ? 'Text' : markerName;
-  }
-  return type;
-}
-
 /**
  * This function takes the intended marker schema for a marker field, and applies
  * the appropriate formatting function.
  */
 export function getSchemaFromMarker(
   markerSchemaByName: MarkerSchemaByName,
-  markerName: string,
   markerData: MarkerPayload | null
 ): MarkerSchema | null {
-  return (
-    markerSchemaByName[
-      getMarkerSchemaName(markerSchemaByName, markerName, markerData)
-    ] || null
-  );
+  const schemaName = markerData ? markerData.type : null;
+  return schemaName ? (markerSchemaByName[schemaName] ?? null) : null;
 }
 
 /**
@@ -385,12 +345,8 @@ export function getLabelGetter(
     // No label exists, it will have to be generated for the first time.
     if (label === undefined) {
       const marker = getMarker(markerIndex);
-      const schemaName = getMarkerSchemaName(
-        markerSchemaByName,
-        marker.name,
-        marker.data
-      );
-      const applyLabel = labelFns.get(schemaName);
+      const schemaName = marker.data ? marker.data.type : null;
+      const applyLabel = schemaName ? labelFns.get(schemaName) : null;
 
       label = applyLabel
         ? // A label function is available, apply it.
diff --git a/src/profile-logic/processed-profile-versioning.js b/src/profile-logic/processed-profile-versioning.js
index 6dc2eec8ca..c50b1067ca 100644
--- a/src/profile-logic/processed-profile-versioning.js
+++ b/src/profile-logic/processed-profile-versioning.js
@@ -1640,27 +1640,26 @@ const _upgraders = {
           // eventType is in the payload as well.
         ],
       },
+
+      // The following three schemas should have just been a single schema named
+      // "tracing". They are kept here for historical accuracy.
+      // The upgrader for version 52 adds the missing "tracing" schema.
       {
-        // TODO - Note that this marker is a "tracing" marker currently.
-        // See issue #2749
         name: 'Paint',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'category', label: 'Type', format: 'string' }],
       },
       {
-        // TODO - Note that this marker is a "tracing" marker currently.
-        // See issue #2749
         name: 'Navigation',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'category', label: 'Type', format: 'string' }],
       },
       {
-        // TODO - Note that this marker is a "tracing" marker currently.
-        // See issue #2749
         name: 'Layout',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'category', label: 'Type', format: 'string' }],
       },
+
       {
         name: 'IPC',
         tooltipLabel: 'IPC — {marker.data.niceDirection}',
@@ -1676,6 +1675,14 @@ const _upgraders = {
         ],
       },
       {
+        // An unused schema for RefreshDriverTick markers.
+        // This schema is not consistent with what post-schema Firefox would
+        // output. Firefox (as of Jan 2025) is still using Text markers and does
+        // not have a RefreshDriverTick schema. Furthermore, upgraded profiles
+        // which get this schema do not have any { type: 'RefreshDriverTick' }
+        // markers - in the past they picked up this schema due to a compat hack,
+        // but this hack is now removed. So this schema is unused. It is kept
+        // here for historical accuracy.
         name: 'RefreshDriverTick',
         display: ['marker-chart', 'marker-table', 'timeline-overview'],
         data: [{ key: 'name', label: 'Tick Reasons', format: 'string' }],
@@ -2270,6 +2277,76 @@ const _upgraders = {
     // marker data with the new field types data, and no modification is needed in the
     // frontend to display older formats.
   },
+  [52]: (profile) => {
+    // This version simplifies how markers are mapped to their schema.
+    // The schema is now purely determined by data.type. The marker's name is ignored.
+    // If a marker has a null data, then it has no schema.
+    //
+    // In earlier versions, there were special cases for mapping markers with type
+    // "tracing" and "Text", and for markers with a null data property. These
+    // special cases have been removed.
+    //
+    // The upgrader for version 52 makes it so that existing profiles appear the
+    // same with the simplified logic. Specifically:
+    //  - Some old profiles have markers with data.type === 'tracing' but no schema
+    //    with the name 'tracing'. To ensure that the tracing markers from these
+    //    profile still show up in the 'timeline-overview' area, this upgrader adds
+    //    a schema to such profiles.
+    //  - Some old profiles have CC markers which only showed up in the memory track
+    //    because of special treatment of 'tracing' markers - the markers would have
+    //    data.type === 'tracing' and data.category === 'CC', and there would be a
+    //    'CC' schema with 'timeline-memory'. This upgrader moves these tracing CC
+    //    markers to a new 'tracingCCFrom52Upgrader' schema.
+    //
+    // Profiles from modern versions of Firefox already include a 'tracing' schema.
+    // And they don't use tracing markers for CC markers.
+
+    const schemaNames = new Set(profile.meta.markerSchema.map((s) => s.name));
+    const kTracingCCSchemaName = 'tracingCCFrom52Upgrader';
+    const shouldMigrateTracingCCMarkers = schemaNames.has('CC');
+    let hasTracingMarkers = false;
+    let hasMigratedTracingCCMarkers = false;
+    for (const thread of profile.threads) {
+      const { markers } = thread;
+      for (let i = 0; i < markers.length; i++) {
+        const data = markers.data[i];
+        if (data && data.type === 'tracing' && data.category) {
+          hasTracingMarkers = true;
+          if (shouldMigrateTracingCCMarkers && data.category === 'CC') {
+            data.type = kTracingCCSchemaName;
+            hasMigratedTracingCCMarkers = true;
+            if (data.interval) {
+              // Also delete the interval property. This is present on old
+              // profiles where marker phase information was represented in the
+              // payload, i.e. you'd have interval: "start" / "end" on the
+              // data object.
+              // Our kTracingCCSchemaName schema does not list the interval field,
+              // so we shouldn't have this field on the payload either.
+              delete data.interval;
+            }
+          }
+        }
+      }
+    }
+    if (hasTracingMarkers && !schemaNames.has('tracing')) {
+      // Make sure that tracing markers still show up in the timeline-overview area.
+      profile.meta.markerSchema.push({
+        name: 'tracing',
+        display: ['marker-chart', 'marker-table', 'timeline-overview'],
+        data: [{ key: 'category', label: 'Type', format: 'string' }],
+      });
+    }
+
+    if (hasMigratedTracingCCMarkers) {
+      // Add the kTracingCCSchemaName schema for migrated tracing CC markers, to
+      // make sure that these markers still show up in the timeline-memory area.
+      profile.meta.markerSchema.push({
+        name: kTracingCCSchemaName,
+        display: ['marker-chart', 'marker-table', 'timeline-memory'],
+        data: [{ key: 'category', label: 'Type', format: 'string' }],
+      });
+    }
+  },
   // If you add a new upgrader here, please document the change in
   // `docs-developer/CHANGELOG-formats.md`.
 };
diff --git a/src/profile-logic/sanitize.js b/src/profile-logic/sanitize.js
index 2ffc6d35fb..2b364959d8 100644
--- a/src/profile-logic/sanitize.js
+++ b/src/profile-logic/sanitize.js
@@ -299,11 +299,8 @@ function sanitizeThreadPII(
 
       if (currentMarker && PIIToBeRemoved.shouldRemoveUrls) {
         // Use the schema to find some properties that need to be sanitized.
-        const markerNameIndex = markerTable.name[i];
-        const markerName = thread.stringTable.getString(markerNameIndex);
         const markerSchema = getSchemaFromMarker(
           markerSchemaByName,
-          markerName,
           currentMarker
         );
         if (markerSchema) {
diff --git a/src/profile-logic/tracks.js b/src/profile-logic/tracks.js
index 4b69c15577..9047854d0d 100644
--- a/src/profile-logic/tracks.js
+++ b/src/profile-logic/tracks.js
@@ -15,7 +15,6 @@ import type {
   Counter,
   Tid,
   TrackReference,
-  MarkerSchemaByName,
   TabID,
 } from 'firefox-profiler/types';
 
@@ -23,7 +22,6 @@ import { defaultThreadOrder, getFriendlyThreadName } from './profile-data';
 import { intersectSets, subtractSets } from '../utils/set';
 import { splitSearchString, stringsToRegExp } from '../utils/string';
 import { ensureExists, assertExhaustiveCheck } from '../utils/flow';
-import { getMarkerSchemaName } from './marker-schema';
 
 export type TracksWithOrder = {|
   +globalTracks: GlobalTrack[],
@@ -258,8 +256,7 @@ export function initializeLocalTrackOrderByPid(
  */
 export function computeLocalTracksByPid(
   profile: Profile,
-  availableGlobalTracks: GlobalTrack[],
-  markerSchemaByName: MarkerSchemaByName
+  availableGlobalTracks: GlobalTrack[]
 ): Map<Pid, LocalTrack[]> {
   const localTracksByPid = new Map();
 
@@ -323,12 +320,8 @@ export function computeLocalTracksByPid(
       for (let i = 0; i < markers.length; ++i) {
         const markerNameIndex = markers.name[i];
         const markerData = markers.data[i];
-        const markerSchemaName = getMarkerSchemaName(
-          markerSchemaByName,
-          thread.stringTable.getString(markerNameIndex),
-          markerData
-        );
-        if (markerData && markerSchemaByName) {
+        const markerSchemaName = markerData ? markerData.type : null;
+        if (markerData && markerSchemaName) {
           const mapEntry = markerTracksBySchemaName.get(markerSchemaName);
           if (mapEntry && mapEntry.keys.every((k) => k in markerData)) {
             mapEntry.markerNames.add(markerNameIndex);
diff --git a/src/selectors/per-thread/markers.js b/src/selectors/per-thread/markers.js
index 393ee3f168..d64ab7e706 100644
--- a/src/selectors/per-thread/markers.js
+++ b/src/selectors/per-thread/markers.js
@@ -11,10 +11,7 @@ import * as MarkerData from '../../profile-logic/marker-data';
 import * as MarkerTimingLogic from '../../profile-logic/marker-timing';
 import * as ProfileSelectors from '../profile';
 import { getRightClickedMarkerInfo } from '../right-clicked-marker';
-import {
-  getLabelGetter,
-  getMarkerSchemaName,
-} from '../../profile-logic/marker-schema';
+import { getLabelGetter } from '../../profile-logic/marker-schema';
 import { getInclusiveSampleIndexRangeForSelection } from '../../profile-logic/profile-data';
 
 import type { BasicThreadSelectorsPerThread } from './thread';
@@ -682,11 +679,7 @@ export function getMarkerSelectorsPerThread(
             if (
               data &&
               marker.name === name &&
-              getMarkerSchemaName(
-                ProfileSelectors.getMarkerSchemaByName,
-                marker.name,
-                data
-              ) === schemaName &&
+              data.type === schemaName &&
               keys.every((key) => key in data)
             ) {
               markerIndexes.push(index);
diff --git a/src/test/components/TimelineMarkers.test.js b/src/test/components/TimelineMarkers.test.js
index b275bf5775..12cd5aa21b 100644
--- a/src/test/components/TimelineMarkers.test.js
+++ b/src/test/components/TimelineMarkers.test.js
@@ -179,12 +179,12 @@ describe('TimelineMarkers', function () {
     window.devicePixelRatio = 1;
 
     const { container } = setupWithMarkers({ rangeStart: 0, rangeEnd: 15 }, [
-      ['DOMEvent', 0, 10],
-      ['DOMEvent', 0, 10],
-      ['DOMEvent', 5, 15],
-      ['Paint', 2, 13],
-      ['Navigation', 2, 6],
-      ['Layout', 6, 8],
+      ['DOMEvent', 0, 10, { type: 'tracing', category: 'JS' }],
+      ['DOMEvent', 0, 10, { type: 'tracing', category: 'JS' }],
+      ['DOMEvent', 5, 15, { type: 'DOMEvent', latency: 3.7, eventType: 'msg' }],
+      ['Paint', 2, 13, { type: 'tracing', category: 'Paint' }],
+      ['Navigation', 2, 6, { type: 'tracing', category: 'Navigation' }],
+      ['Layout', 6, 8, { type: 'tracing', category: 'Layout' }],
       // These 2 will be ignored.
       ['CC', 0, 5],
       ['GCMajor', 5, 10],
@@ -205,7 +205,7 @@ describe('TimelineMarkers', function () {
       { rangeStart: 0, rangeEnd: 15, component: TimelineMarkersMemory },
       [
         // The first one will be ignored.
-        ['DOMEvent', 0, 10],
+        ['DOMEvent', 0, 10, { type: 'tracing', category: 'JS' }],
         ['CC', 0, 5],
         ['GCMajor', 5, 10],
       ]
@@ -253,7 +253,7 @@ describe('TimelineMarkers', function () {
       { rangeStart: 0, rangeEnd: 10 },
       [
         ['DOMEvent', 0, 3],
-        ['Navigation', 6, 10],
+        ['Load', 6, 10, { type: 'tracing', category: 'Navigation' }],
       ]
     );
 
@@ -300,7 +300,7 @@ describe('TimelineMarkers', function () {
         { rangeStart: 0, rangeEnd: 10 },
         [
           ['DOMEvent', 0, 3],
-          ['Navigation', 6, 10],
+          ['Load', 6, 10, { type: 'tracing', category: 'Navigation' }],
         ]
       );
 
@@ -315,7 +315,7 @@ describe('TimelineMarkers', function () {
       expect(getContextMenu()).toHaveClass('react-contextmenu--visible');
 
       clickOnMenuItem('Copy description');
-      expect(copy).toHaveBeenLastCalledWith('Navigation');
+      expect(copy).toHaveBeenLastCalledWith('Load');
 
       expect(getContextMenu()).not.toHaveClass('react-contextmenu--visible');
 
diff --git a/src/test/components/__snapshots__/MenuButtons.test.js.snap b/src/test/components/__snapshots__/MenuButtons.test.js.snap
index 97eefd2356..0e79a8879f 100644
--- a/src/test/components/__snapshots__/MenuButtons.test.js.snap
+++ b/src/test/components/__snapshots__/MenuButtons.test.js.snap
@@ -2211,7 +2211,7 @@ exports[`app/MenuButtons <Publish> matches the snapshot for the menu buttons and
           class="menuButtonsDownloadSize"
         >
           (
-          1.65 kB
+          1.63 kB
           )
         </span>
       </a>
@@ -2329,7 +2329,7 @@ exports[`app/MenuButtons <Publish> matches the snapshot for the opened panel for
           class="menuButtonsDownloadSize"
         >
           (
-          1.63 kB
+          1.61 kB
           )
         </span>
       </a>
@@ -2442,7 +2442,7 @@ exports[`app/MenuButtons <Publish> matches the snapshot for the opened panel for
           class="menuButtonsDownloadSize"
         >
           (
-          1.65 kB
+          1.63 kB
           )
         </span>
       </a>
diff --git a/src/test/fixtures/profiles/marker-schema.js b/src/test/fixtures/profiles/marker-schema.js
index 8a783bd024..4a1ddf7e23 100644
--- a/src/test/fixtures/profiles/marker-schema.js
+++ b/src/test/fixtures/profiles/marker-schema.js
@@ -144,26 +144,13 @@ export const markerSchemaForTests: MarkerSchema[] = [
     ],
   },
   {
-    // TODO - Note that this marker is a "tracing" marker currently.
-    // See issue #2749
-    name: 'Paint',
+    name: 'tracing',
     display: ['marker-chart', 'marker-table', 'timeline-overview'],
     data: [
       { key: 'category', label: 'Type', format: 'string', searchable: true },
     ],
   },
   {
-    // TODO - Note that this marker is a "tracing" marker currently.
-    // See issue #2749
-    name: 'Navigation',
-    display: ['marker-chart', 'marker-table', 'timeline-overview'],
-    data: [
-      { key: 'category', label: 'Type', format: 'string', searchable: true },
-    ],
-  },
-  {
-    // TODO - Note that this marker is a "tracing" marker currently.
-    // See issue #2749
     name: 'Layout',
     display: ['marker-chart', 'marker-table', 'timeline-overview'],
     data: [
@@ -185,16 +172,9 @@ export const markerSchemaForTests: MarkerSchema[] = [
     ],
   },
   {
-    name: 'RefreshDriverTick',
+    name: 'VisibleInTimelineOverview',
     display: ['marker-chart', 'marker-table', 'timeline-overview'],
-    data: [
-      {
-        key: 'name',
-        label: 'Tick Reasons',
-        format: 'string',
-        searchable: true,
-      },
-    ],
+    data: [],
   },
   {
     name: 'StringTesting',
diff --git a/src/test/fixtures/profiles/processed-profile.js b/src/test/fixtures/profiles/processed-profile.js
index c3e9de110c..fe96acb72a 100644
--- a/src/test/fixtures/profiles/processed-profile.js
+++ b/src/test/fixtures/profiles/processed-profile.js
@@ -62,17 +62,23 @@ type MarkerName = string;
 type MarkerTime = Milliseconds;
 
 // These markers can create an Instant or a complete Interval marker, depending
-// on if an end time is passed in. The definition uses a union, becaus as far
+// on if an end time is passed in.
+//
+// If the data field is left out (undefined), a default value { type: MarkerName }
+// is used. If the data field is manually set to null, a null data is used.
+//
+// The definition uses a union, becaus as far
 // as I can tell, Flow doesn't support multiple arity tuples.
 export type TestDefinedMarkers = Array<
-  // Instant marker:
+  // Instant marker, payload defaulting to { type: MarkerName }:
   | [MarkerName, MarkerTime]
-  // No payload:
+  // Interval marker:
   | [
       MarkerName,
       MarkerTime, // start time
       MarkerTime | null, // end time
     ]
+  // Marker with manual payload:
   | [
       MarkerName,
       MarkerTime, // start time
@@ -165,7 +171,8 @@ export function addMarkersToThreadWithCorrespondingSamples(
     const startTime = tuple[1];
     // Flow doesn't support variadic tuple types.
     const maybeEndTime = (tuple: any)[2] || null;
-    const payload: MarkerPayload | null = (tuple: any)[3] || null;
+    const maybePayload: MarkerPayload | null | void = (tuple: any)[3];
+    const payload = maybePayload === undefined ? { type: name } : maybePayload;
 
     markersTable.name.push(stringTable.indexForString(name));
     if (maybeEndTime === null) {
@@ -184,7 +191,7 @@ export function addMarkersToThreadWithCorrespondingSamples(
       markerSchemaForTests,
       stringTable
     );
-    markersTable.data.push(payload);
+    markersTable.data.push((payload: any));
     markersTable.category.push(0);
     markersTable.length++;
   });
diff --git a/src/test/integration/symbolicator-cli/__snapshots__/symbolicator-cli.test.js.snap b/src/test/integration/symbolicator-cli/__snapshots__/symbolicator-cli.test.js.snap
index de1ddacb60..9f03640ed2 100644
--- a/src/test/integration/symbolicator-cli/__snapshots__/symbolicator-cli.test.js.snap
+++ b/src/test/integration/symbolicator-cli/__snapshots__/symbolicator-cli.test.js.snap
@@ -88,7 +88,7 @@ Object {
     "markerSchema": Array [],
     "oscpu": "macOS 14.6.1",
     "pausedRanges": Array [],
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "a.out",
     "sampleUnits": Object {
diff --git a/src/test/store/__snapshots__/markers.test.js.snap b/src/test/store/__snapshots__/markers.test.js.snap
index 7ecb6b42d7..b66d251669 100644
--- a/src/test/store/__snapshots__/markers.test.js.snap
+++ b/src/test/store/__snapshots__/markers.test.js.snap
@@ -17,7 +17,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "TTI",
+    },
     "end": null,
     "name": "TTI",
     "start": 6,
@@ -49,7 +51,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "FirstContentfulPaint",
+    },
     "end": 8,
     "name": "FirstContentfulPaint",
     "start": 7,
diff --git a/src/test/store/__snapshots__/profile-view.test.js.snap b/src/test/store/__snapshots__/profile-view.test.js.snap
index 138d5480f8..0ce6dd13ba 100644
--- a/src/test/store/__snapshots__/profile-view.test.js.snap
+++ b/src/test/store/__snapshots__/profile-view.test.js.snap
@@ -335,23 +335,7 @@ Object {
           "marker-table",
           "timeline-overview",
         ],
-        "name": "Paint",
-      },
-      Object {
-        "data": Array [
-          Object {
-            "format": "string",
-            "key": "category",
-            "label": "Type",
-            "searchable": true,
-          },
-        ],
-        "display": Array [
-          "marker-chart",
-          "marker-table",
-          "timeline-overview",
-        ],
-        "name": "Navigation",
+        "name": "tracing",
       },
       Object {
         "data": Array [
@@ -403,20 +387,13 @@ Object {
         "tooltipLabel": "IPC — {marker.data.niceDirection}",
       },
       Object {
-        "data": Array [
-          Object {
-            "format": "string",
-            "key": "name",
-            "label": "Tick Reasons",
-            "searchable": true,
-          },
-        ],
+        "data": Array [],
         "display": Array [
           "marker-chart",
           "marker-table",
           "timeline-overview",
         ],
-        "name": "RefreshDriverTick",
+        "name": "VisibleInTimelineOverview",
       },
       Object {
         "data": Array [
@@ -457,7 +434,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "sourceURL": "",
@@ -996,12 +973,24 @@ Object {
           0,
         ],
         "data": Array [
-          null,
-          null,
-          null,
-          null,
-          null,
-          null,
+          Object {
+            "type": "A",
+          },
+          Object {
+            "type": "B",
+          },
+          Object {
+            "type": "C",
+          },
+          Object {
+            "type": "D",
+          },
+          Object {
+            "type": "E",
+          },
+          Object {
+            "type": "F",
+          },
           Object {
             "URI": "https://mozilla.org",
             "endTime": 6.5,
@@ -1678,12 +1667,24 @@ Array [
         0,
       ],
       "data": Array [
-        null,
-        null,
-        null,
-        null,
-        null,
-        null,
+        Object {
+          "type": "A",
+        },
+        Object {
+          "type": "B",
+        },
+        Object {
+          "type": "C",
+        },
+        Object {
+          "type": "D",
+        },
+        Object {
+          "type": "E",
+        },
+        Object {
+          "type": "F",
+        },
         Object {
           "URI": "https://mozilla.org",
           "endTime": 6.5,
@@ -1841,7 +1842,9 @@ exports[`snapshots of selectors/profile matches the last stored run of markerThr
 Array [
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "D",
+    },
     "end": null,
     "name": "D",
     "start": 3,
@@ -1849,7 +1852,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "E",
+    },
     "end": null,
     "name": "E",
     "start": 4,
@@ -1857,7 +1862,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "F",
+    },
     "end": null,
     "name": "F",
     "start": 5,
@@ -1908,7 +1915,9 @@ exports[`snapshots of selectors/profile matches the last stored run of markerThr
 Array [
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "A",
+    },
     "end": null,
     "name": "A",
     "start": 0,
@@ -1916,7 +1925,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "B",
+    },
     "end": null,
     "name": "B",
     "start": 1,
@@ -1924,7 +1935,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "C",
+    },
     "end": null,
     "name": "C",
     "start": 2,
@@ -1932,7 +1945,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "D",
+    },
     "end": null,
     "name": "D",
     "start": 3,
@@ -1940,7 +1955,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "E",
+    },
     "end": null,
     "name": "E",
     "start": 4,
@@ -1948,7 +1965,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "F",
+    },
     "end": null,
     "name": "F",
     "start": 5,
@@ -2068,7 +2087,9 @@ exports[`snapshots of selectors/profile matches the last stored run of markerThr
 Array [
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "D",
+    },
     "end": null,
     "name": "D",
     "start": 3,
@@ -2076,7 +2097,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "E",
+    },
     "end": null,
     "name": "E",
     "start": 4,
@@ -2084,7 +2107,9 @@ Array [
   },
   Object {
     "category": 0,
-    "data": null,
+    "data": Object {
+      "type": "F",
+    },
     "end": null,
     "name": "F",
     "start": 5,
diff --git a/src/test/store/markers.test.js b/src/test/store/markers.test.js
index 61450e3768..b14784ee37 100644
--- a/src/test/store/markers.test.js
+++ b/src/test/store/markers.test.js
@@ -2,10 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 // @flow
-import {
-  selectedThreadSelectors,
-  getMarkerSchemaByName,
-} from 'firefox-profiler/selectors';
+import { selectedThreadSelectors } from 'firefox-profiler/selectors';
 import { changeTimelineTrackOrganization } from 'firefox-profiler/actions/receive-profile';
 import { unserializeProfileOfArbitraryFormat } from 'firefox-profiler/profile-logic/process-profile';
 import { ensureExists } from 'firefox-profiler/utils/flow';
@@ -227,10 +224,10 @@ describe('memory markers', function () {
 
     return storeWithProfile(
       getProfileWithMarkers([
-        ['DOMEvent', 0, null],
-        ['Navigation', 1, null],
-        ['Paint', 2, null],
-        ['IdleForgetSkippable', 3, 4, { type: 'tracing', category: 'CC' }],
+        ['DOMEvent', 0, null, { type: 'tracing', category: 'JS' }],
+        ['Navigation', 1, null, { type: 'tracing', category: 'Navigation' }],
+        ['Paint', 2, null, { type: 'tracing', category: 'Paint' }],
+        ['IdleForgetSkippable', 3, 4, { type: 'CC' }],
         ['GCMinor', 5, null, { type: 'GCMinor', nursery: any }],
         ['GCMajor', 6, null, { type: 'GCMajor', timings: any }],
         ['GCSlice', 7, null, { type: 'GCSlice', timings: any }],
@@ -419,7 +416,8 @@ describe('Marker schema filtering', function () {
     const profile = getProfileWithMarkers([
       ['no payload',        0, null, null],
       ['payload no schema', 0, null, { type: 'no schema marker' }],
-      ['RefreshDriverTick', 0, null, { type: 'Text', name: 'RefreshDriverTick' }],
+      ['RefreshDriverTick', 0, null, { type: 'Text', name: 'Tick with 1 observer' }],
+      ['VisibleInTimelineOverview', 0, null],
       ['UserTiming',        5, 6,    { type: 'UserTiming', name: 'name', entryType: 'mark' }],
       // The following is a tracing marker without a schema attached, this was a
       // regression reported in Bug 1678698.
@@ -432,15 +430,6 @@ describe('Marker schema filtering', function () {
   function setup(profile) {
     const { getState } = storeWithProfile(profile);
     const getMarker = selectedThreadSelectors.getMarkerGetter(getState());
-    const markerSchemaByName = getMarkerSchemaByName(getState());
-
-    if (markerSchemaByName.RandomTracingMarker) {
-      throw new Error(
-        'This test assumes that the RandomTracingMarker marker has no schema. If this ' +
-          'schema were added somewhere else, then rename RandomTracingMarker to ' +
-          'something else. '
-      );
-    }
 
     function getMarkerNames(selector): string[] {
       return selector(getState())
@@ -459,6 +448,7 @@ describe('Marker schema filtering', function () {
       'no payload',
       'payload no schema',
       'RefreshDriverTick',
+      'VisibleInTimelineOverview',
       'Load 0: https://mozilla.org',
       'UserTiming',
       'RandomTracingMarker',
@@ -473,6 +463,7 @@ describe('Marker schema filtering', function () {
       'no payload',
       'payload no schema',
       'RefreshDriverTick',
+      'VisibleInTimelineOverview',
       'Load 0: https://mozilla.org',
       'UserTiming',
       'RandomTracingMarker',
@@ -664,7 +655,7 @@ describe('Marker schema filtering', function () {
     const { getMarkerNames } = setup(getProfileForMarkerSchema());
     expect(
       getMarkerNames(selectedThreadSelectors.getTimelineOverviewMarkerIndexes)
-    ).toEqual(['RefreshDriverTick']);
+    ).toEqual(['VisibleInTimelineOverview', 'RandomTracingMarker']);
   });
 });
 
diff --git a/src/test/unit/__snapshots__/profile-conversion.test.js.snap b/src/test/unit/__snapshots__/profile-conversion.test.js.snap
index 59355ebd9d..6d0f6a837f 100644
--- a/src/test/unit/__snapshots__/profile-conversion.test.js.snap
+++ b/src/test/unit/__snapshots__/profile-conversion.test.js.snap
@@ -469,7 +469,7 @@ Object {
     "oscpu": undefined,
     "physicalCPUs": undefined,
     "platform": undefined,
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "ART Trace (Android)",
     "sampleUnits": undefined,
@@ -100220,7 +100220,7 @@ Object {
     "oscpu": undefined,
     "physicalCPUs": undefined,
     "platform": undefined,
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "ART Trace (Android)",
     "sampleUnits": undefined,
@@ -382162,7 +382162,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Chrome Trace",
     "profilingEndTime": 119159778.026,
@@ -430868,7 +430868,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Chrome Trace",
     "profilingEndTime": 119159778.026,
@@ -479574,7 +479574,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Chrome Trace",
     "profilingEndTime": 66155012.423,
@@ -482616,7 +482616,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Chrome Trace",
     "sourceURL": "",
@@ -485734,7 +485734,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Chrome Trace",
     "profilingEndTime": 355035987.653,
@@ -489802,7 +489802,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Chrome Trace",
     "profilingEndTime": 66155012.423,
@@ -491002,7 +491002,7 @@ Object {
     "oscpu": undefined,
     "physicalCPUs": undefined,
     "platform": undefined,
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "sampleUnits": undefined,
@@ -498527,7 +498527,7 @@ Object {
     "oscpu": undefined,
     "physicalCPUs": undefined,
     "platform": undefined,
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "sampleUnits": undefined,
@@ -517940,7 +517940,7 @@ Object {
     "oscpu": undefined,
     "physicalCPUs": undefined,
     "platform": undefined,
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "sampleUnits": undefined,
@@ -525458,7 +525458,7 @@ Object {
     "oscpu": undefined,
     "physicalCPUs": undefined,
     "platform": undefined,
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "sampleUnits": undefined,
@@ -549052,7 +549052,7 @@ Object {
     "keepProfileThreadOrder": true,
     "markerSchema": Array [],
     "platform": "Android",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "com.example.sampleapplication",
     "sourceCodeIsNotOnSearchfox": true,
@@ -640488,7 +640488,7 @@ Object {
     "keepProfileThreadOrder": true,
     "markerSchema": Array [],
     "platform": "Android",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "com.example.sampleapplication",
     "sourceCodeIsNotOnSearchfox": true,
@@ -740767,7 +740767,7 @@ Object {
     "oscpu": "",
     "physicalCPUs": 0,
     "platform": "",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "target/debug/examples/work_log (dhat)",
     "sourceURL": "",
diff --git a/src/test/unit/__snapshots__/profile-upgrading.test.js.snap b/src/test/unit/__snapshots__/profile-upgrading.test.js.snap
index f45bdfb44e..badcd1800b 100644
--- a/src/test/unit/__snapshots__/profile-upgrading.test.js.snap
+++ b/src/test/unit/__snapshots__/profile-upgrading.test.js.snap
@@ -40,7 +40,7 @@ Object {
     "oscpu": undefined,
     "physicalCPUs": undefined,
     "platform": undefined,
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "sampleUnits": undefined,
@@ -10967,11 +10967,26 @@ Object {
         ],
         "name": "Network",
       },
+      Object {
+        "data": Array [
+          Object {
+            "format": "string",
+            "key": "category",
+            "label": "Type",
+          },
+        ],
+        "display": Array [
+          "marker-chart",
+          "marker-table",
+          "timeline-overview",
+        ],
+        "name": "tracing",
+      },
     ],
     "misc": "rv:48.0",
     "oscpu": "Intel Mac OS X 10.11",
     "platform": "Macintosh",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "stackwalk": 1,
@@ -12621,11 +12636,26 @@ Object {
         ],
         "name": "Network",
       },
+      Object {
+        "data": Array [
+          Object {
+            "format": "string",
+            "key": "category",
+            "label": "Type",
+          },
+        ],
+        "display": Array [
+          "marker-chart",
+          "marker-table",
+          "timeline-overview",
+        ],
+        "name": "tracing",
+      },
     ],
     "misc": "rv:48.0",
     "oscpu": "Intel Mac OS X 10.11",
     "platform": "Macintosh",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "stackwalk": 1,
@@ -14418,11 +14448,26 @@ Object {
         ],
         "name": "Network",
       },
+      Object {
+        "data": Array [
+          Object {
+            "format": "string",
+            "key": "category",
+            "label": "Type",
+          },
+        ],
+        "display": Array [
+          "marker-chart",
+          "marker-table",
+          "timeline-overview",
+        ],
+        "name": "tracing",
+      },
     ],
     "misc": "rv:48.0",
     "oscpu": "Intel Mac OS X 10.11",
     "platform": "Macintosh",
-    "preprocessedProfileVersion": 51,
+    "preprocessedProfileVersion": 52,
     "processType": 0,
     "product": "Firefox",
     "stackwalk": 1,
diff --git a/src/types/profile.js b/src/types/profile.js
index 03bfe096ab..719dadcd6f 100644
--- a/src/types/profile.js
+++ b/src/types/profile.js
@@ -227,18 +227,6 @@ export type NativeAllocationsTable =
   | UnbalancedNativeAllocationsTable
   | BalancedNativeAllocationsTable;
 
-/**
- * This is the base abstract class that marker payloads inherit from. This probably isn't
- * used directly in profiler.firefox.com, but is provided here for mainly documentation
- * purposes.
- */
-export type ProfilerMarkerPayload = {
-  type: string,
-  startTime?: Milliseconds,
-  endTime?: Milliseconds,
-  stack?: Thread,
-};
-
 /**
  * Markers represent arbitrary events that happen within the browser. They have a
  * name, time, and potentially a JSON data payload. These can come from all over the