The context is that I'm trying to build 2026 WebKit for Tiger on Intel, it's going surprisingly well. CSS 3D was a big question mark before this discovery, fonts were also a gap before discovering that Core Text was already in 10.4 as a private framework.
It's not gonna run anywhere Tiger runs; it's heavily tuned for 64-bit Intel. But it should be enough to run actual JS-based pages and maybe even playback 720p video. 10.4 technically supports 64-bit processes, but only headless ones. Certainly not AppKit. So I'm experimenting with different splits (64-bit JSCore, 32-bit renderer, 64-bit everything minus the window chrome at the expense of native rendering, etc)
anyway in 2007 Apple secretly backported the prerelease implementation of Core Animation (nee LayerKit) to the Tiger fork used by the original Apple TV, so I extracted the Apple TV binary, transplanted it into Tiger, resolved its private framework dependencies, and now Tiger has Core Animation. it's a christmas miracle