Clean ownership boundary — OwnedMediaRegistry replaces the fragile dataset.hfSlideshowMediaSync marker with AbortController-per-binding, and the 10-cycle reconnect test pins the idempotence contract cleanly. The el.ownerDocument.defaultView?.AbortController ?? AbortController fallback for cross-realm iframe media is a nice touch.

Nits

• packages/player/src/slideshow/hyperframes-slideshow.ts:1170 — stopDocumentMedia now stops only owned media, not document-wide. The name is left over from the old ownerDocument.querySelectorAll implementation. Consider stopOwnedMedia (or similar) to match the registry's actual scope. Trivial; ignore if you'd rather keep the internal API stable.
• packages/player/src/slideshow/hyperframes-slideshow.ts:1163-1174 — updateMutedState and stopDocumentMedia both call ownedMedia.sync(...) directly instead of routing through wireSlideshowMedia(). If a new element gets picked up by updateMutedState's call, its initial mute state is applied by the immediately-following setMuted(muted) (bounded set, single-threaded — safe), but the added-mute path from wireSlideshowMedia is duplicated. Consistent as-is; flagging in case you'd rather have one entry point.

What I didn't verify

• Cross-realm AbortController behavior in Firefox / older Safari — trusting the pattern generalizes to your target matrix.
• Whether any consumer outside packages/player relied on the old page-wide mute/pause semantics of <hyperframes-slideshow>. Workspace grep turned up none; the PR body explicitly calls the scope reduction a fix.

— Review by Rames D Jusso

Independent bottom-layer review on 16942c0c.

• Reconnect teardown/recreation is symmetric for controls and parent media (packages/player/src/hyperframes-player.ts:179, :192).
• The registry uses owner-realm AbortControllers and aborts removed/disconnected bindings (packages/player/src/slideshow/owned-media-registry.ts:35, :46, :67).
• Scope tests cover two slideshows plus unrelated page media (packages/player/src/slideshow/hyperframes-slideshow.test.ts:397).

Rames already covered the naming/entry-point nits; I found no additional correctness gap. Current required checks are green.

Verdict: APPROVE
Reasoning: Resource ownership is bounded to the component, teardown is deterministic, and reconnect/scope regressions are directly tested.

— Home

Re-reviewed the merged head 16942c0c12fab7e87876fa253432e29d85835db4. There is no new code delta since my approval, and the completed required checks are green. I found no post-merge correctness issue. The earlier naming / duplicate sync-entry-point notes remain optional cleanup only.

Verdict: COMMENT (post-merge: Ready)
Reasoning: Same approved head, green required CI, and no newly discovered blocker.
— Magi

Final freshness check on merged head 16942c0c12fab7e87876fa253432e29d85835db4.

The reviewed commit is unchanged, the player-ownership boundary remains clean, and the complete required check set is green. No post-merge regression or new review finding surfaced.

Verdict: COMMENT (post-merge ready)
Reasoning: The merged implementation remains sound and fully green; there is no actionable follow-up from this pass.

— Deepwork