https://compat.spec.whatwg.org/#windoworientation-interface Our implementation is only on platforms with an orientation concept, but the specification says it should be everywhere. That is straightforward to do.
<rdar://problem/102110117>
Pull request: https://github.com/WebKit/WebKit/pull/6269
Committed 256469@main (052d5b6a2ca0): <https://commits.webkit.org/256469@main> Reviewed commits have been landed. Closing PR #6269 and removing active labels.
The spec (https://compat.spec.whatwg.org/#windoworientation-interface) says: "User agents implementing the window.orientation attribute and its associated orientationchange event must not expose them on non-Mobile platforms." Firefox and Chrome both don't expose this on Desktop. We have evidence of site breakage from this (rdar://106273441). I think we should revert.