DRAFT: PR for enhancing WP_Scripts with a loading strategy

src/wp-content/themes/twentytwentyone/functions.php

@@ -425,7 +425,7 @@ function twenty_twenty_one_scripts() {
 		get_template_directory_uri() . '/assets/js/polyfills.js',
 		array(),
 		wp_get_theme()->get( 'Version' ),
-		true
+		array( 'in_footer' => true )
 	);
 
 	// Register the IE11 polyfill loader.
@@ -434,7 +434,7 @@ function twenty_twenty_one_scripts() {
 		null,
 		array(),
 		wp_get_theme()->get( 'Version' ),
-		true
+		array( 'in_footer' => true )
 	);
 	wp_add_inline_script(
 		'twenty-twenty-one-ie11-polyfills',

src/wp-includes/blocks.php

@@ -153,7 +153,8 @@ function register_block_script_handle( $metadata, $field_name, $index = 0 ) {
 		$script_handle,
 		$script_uri,
 		$script_dependencies,
-		isset( $script_asset['version'] ) ? $script_asset['version'] : false
+		isset( $script_asset['version'] ) ? $script_asset['version'] : false,
+		array( 'in_footer' => false )
 	);
 	if ( ! $result ) {
 		return false;