Merge branch 'master' into worktree-mosaic-library

# Conflicts:
#	docs/traceability.md

src-tauri/src/repository/device_profile.rs

@@ -65,10 +65,18 @@ const FALLBACK_AUDIO_CODEC: &str = "aac";
 /// play the **video** can decode.
 ///
 /// The platform list comes from `MediaCodecList`, which describes ExoPlayer —
-/// but video does not play through ExoPlayer. Both Android and Linux render it
-/// in a webview `<video>` element, and Chromium/WebKit decode a much smaller set
-/// than the platform does. Advertising the raw list makes Jellyfin direct-play a
-/// track the webview cannot decode, and the user gets picture with no sound.
+/// but the webview `<video>` element may be what renders the video, and
+/// Chromium/WebKit decode a much smaller set than the platform does. Advertising
+/// the raw list makes Jellyfin direct-play a track the webview cannot decode, and
+/// the user gets picture with no sound.
+///
+/// Which renderer gets it is not fixed: Linux is always the element, and Android
+/// follows `experimentalNativeVideo`, which took ExoPlayer as its default in
+/// DR-161 but is a user setting either way. So the *narrow* list is the only one
+/// that holds on both sides of that switch. The cost is a Dolby-licensed Android
+/// device transcoding an E-AC-3 track its ExoPlayer could have direct-played;
+/// the alternative is silence for everyone the switch lands the other way, which
+/// is the bug this exists to prevent.
 ///
 /// The gap is widest on devices whose vendor licenses Dolby: a phone with
 /// `c2.dolby.eac3.decoder` reports `eac3`, so it — and only it — gets a silent