We're in an age where important video and audio online may be deleted without warning and without any ability to find it elsewhere. There's a very useful tool which lets you store an offline copy of video and audio called YT-DLP:

github.com/yt-dlp/yt-dlp

I don't normally like command line tools, but this is pretty easy to use. After you've installed it, you just type yt-dlp and then the URL of the video or audio, then it saves it as a DRM-free file on your computer.

It works with a variety of different video and audio platforms.

(This replaces an earlier tool called yt-dl which is no longer maintained.)

#YouTube

GitHub - yt-dlp/yt-dlp: A feature-rich command-line audio/video downloader

A feature-rich command-line audio/video downloader - yt-dlp/yt-dlp

^GitHub