YouTube already has ToS on their API and has paid tiers. But a lot (most?) of the third-party apps and tools bypass the API and directly scrape the site.
Sorry it wasn’t meant to be. I just thought it was funny that they’re taking advantage of VideoLAN’s library (which is presumably open source) rather than their own.
Hey, sorry for taking so long to get back to you! It looks like the forked version is having issues with hosting on GitLab. :( As a temporary measure, they’re publishing just the releases on GitHub. Here is some more info.