I think it's probably just a large file, as I remember thinking the same thing but it was loaded when I returned to the browser tab with the readme later on.
__264516 Feb 12 11:44 pgassistant.gif
22782965 Feb 12 11:46 pgassistant.gif.raw.gif
_2120322 Feb 12 11:55 pgassistant.gif.av1-20.mp4
__245780 Feb 12 11:56 pgassistant.gif.av1-55.mp4
NEARLY everything can use AV1 and you don't need your clients to install a licensed codec if their OS didn't happen to include one. https://caniuse.com/av1 Far more than https://caniuse.com/hevc
I'm trying but it turns out that it's impossible to submit a useful PR with a video embed in `README.md` because the only way it works is by uploading the video through the web editor[0] and using a static user-images.githubusercontent.com URL.
[0] Which puts it under your account, obvs., and is therefore not that helpful for a PR.