Nothing here invents a new way of tracking changes. Every edit is a normal Git commit in your own repository, which is exactly what makes it safe to let someone else make one.
Every change is a commit
When someone edits a file, it is committed with a message describing the change. It appears in your history alongside everything else, attributable and reviewable.
Reading and undoing
You can view the history of any file and restore an earlier version. A restore is itself a new commit, so the record of what happened stays intact — nothing is rewritten behind you.
It is still your repository
Everything remains visible in GitHub, in your normal tooling. If you stop using this tomorrow, your repository is unchanged and complete. There is no lock-in to escape.