AVIF is based on AV1, a modern video format developed by the Alliance for Open Media (AOMedia). Mozilla is also a member of it. Firefox 86 will be the first browser version with the official AVIF support.
Tag: Firefox AVIF Support
Enable AVIF Support in Mozilla Firefox
How to Enable AVIF Support in Mozilla Firefox
Starting in Mozilla Firefox 77, which is in the Beta channel as of this writing, it is possible to turn on the AVIF image format support in the browser. This can be useful for web sites that actively use this modern format to deliver rich multimedia contents to the end user.