What are the supported formats for `<amp-anim>`

Question

I cannot find anywhere here what file formats are supported beside .gif. Are .gifv or webm include on this extension or is <amp-video> the intended tag for these formats and <amp-anim> is only meant for .gif?

Answer 1

Personally, I understand

A runtime-managed animated image - most typically a GIF.

as

anything that is an image, but not a video

So as long as a browser would be able to render it using an <img> tag and it's animated, then it probably qualifies for using <amp-anim>.