The webcam is a hilarious example. Reminds me of this 1-dimensional video game you can play in your address bar. http://glench.com/hash/
It makes so much sense it hurts, especially when we think of desktop links, home page pins, etc.
The whole "bundle multiple sizes of animated files into one container" is crazy when they are nearly always different resolutions of precisely the same file.
If we have SVG we could modify the SVG at runtime to have it display additional data really easily.
As for video in favicons... kill me now. SVGs and a strict limit on favicon sizes would be good (enforced by browsers, ditch anything over 50KB - it should be more than enough!).
A nice bug I saw recently was that a server could be instructed to send an infinitely sized favicon, and the browser would happily consume it. Nice way to drain a phone battery, use all of the connection bandwidth, and just to play havoc.
What I want from favicons:
2) SVG support for icons in all major OS's so that desktop links and homepage links just work as SVG
3) Max-size enforced by browsers
You want your favicon asset on the same domain serving the page otherwise there is a bunch of CORS work.
For us non-lawyers, what does this mean?
it's from 2013, still works in FF, chrome seems to have changed the way they handle changes in the favicon.
I for one would be very curious to read about how this works (too lazy to read code right now!)...