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

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.