I mean the PR data. The main advantage of a forge like Github are being web browseable, working great as a backup, and the PRs (and other stuff like artifacts storage and CI). All of these have alternatives and are optional. And the API is comprehensive enough to not feel locked in.
Alternatively I could stick with git(1) which does all of this stuff out of the box. Instead of having to learn a superflouous (for the job) API.