Ah ok! We'll be sure to drop looping support from Animated GIFs too, because that's also non-standard[0] and is just an extension Netscape 2.0 slapped on there.
I regret to inform you the vast majority of the web is just Shit People Tried and that became popular enough for everyone else to support, with lots of hacks to make things interoperate better.
They just extended the COLR spec to COLRv1 which essentially is a whole new canvas API in fonts: https://github.com/googlefonts/colr-gradients-spec/blob/main...
That whole section needs to go. Don't embrace any non-standard stuff. Fortunately support is poor, so let's hope Google doesn't add support for this in Chrome or it may become popular enough that everyone has to support it.