pport is enabled by default (yes, again, for the fourth time) and looks to be the biggest feature of Firefox 92, which is expected to see the light of day next month on September 7th.
Mozilla kept delaying AVIF support by default because they wanted to implement more features like transparency and other advanced features, and it looks like Firefox 92 beta comes with support for the new AVIF (AV1 Image File Format) image format, which is based on the modern and royalty free AV1 video codec to provide users with significant bandwidth savings.