src/libraries/System.IO.Compression/src/System/IO/Compression/WinZipAes.PlatformNotSupported.cs:9

• WinZipAesKeyMaterial is declared with a trailing ; (a forward declaration), which is not valid C# syntax and will fail compilation for browser TFMs. Define an empty struct body instead so the browser stub can satisfy references from the rest of the ZIP code.

    internal readonly struct WinZipAesKeyMaterial;

src/libraries/System.IO.Compression/src/System/IO/Compression/WinZipAes.PlatformNotSupported.cs:9

• internal readonly struct WinZipAesKeyMaterial; is not valid C# syntax (C# doesn't support forward declarations). This will fail to compile the browser target. Define an (empty) struct type instead so the rest of the code can reference it.

    internal readonly struct WinZipAesKeyMaterial;

src/libraries/System.IO.Compression/src/System/IO/Compression/ZipCryptoStream.Random.BrowserOrWasi.cs:18

• PR description says ZipCrypto header randomness is generated with Guid.NewGuid(), but the implementation uses Interop.Sys.GetCryptographicallySecureRandomBytes on browser/wasi (and RandomNumberGenerator.Fill elsewhere). Please update the PR description (or code) so the documented approach matches what actually shipped.

            // System.Security.Cryptography's RandomNumberGenerator is not referenced on browser and is
            // not supported on wasi, so call the shared native CSPRNG directly. It is backed by
            // crypto.getRandomValues() on browser and by wasi:random (getentropy/__wasi_random_get) on wasi.
            Span<byte> randomBytes = header.Slice(0, 10);
            fixed (byte* pRandomBytes = randomBytes)
            {
                if (Interop.Sys.GetCryptographicallySecureRandomBytes(pRandomBytes, randomBytes.Length) != 0)
                {
                    throw new IOException(SR.UnableToGenerateRandomBytes);