The beta stitches together fetch logs, thumbnail fetches, and structured media fields. Teams that mix YouTube embeds with first-party HLS players finally get a unified error code for “player not discoverable.”
If you rely on client-only players, expect “deferred discovery” warnings until a noscript or server path exposes a stable poster URL.
Rollout is percentage-based; property-level opt-in forms will close once capacity is reached.