“Bitbucket is a code management service. It is much better than the Git code management service”

In this context it’s even funnier

But pretty much in the same way as the YouTube’s frontend requesting content from YouTube’s backend. This is an equivalent of you loading a video on YouTube then going to developer tools and copying links from the Network tab. AFAIK all tools (Invidious, Piped, yt-dl) work this way.