The commits.php page has a long history dating back to 2006 in GitHub and before that in another repo.
Soon, it is going away. The justification is in issue 337: it’s not used much, and it’s not doing as it should (loading the last 100 commits).
In the early days, the front page showed only a few commits. Loading the commits from the database was intensive. Caching hadn’t been implemented yet. I’m sure better queries had not been developed. If you wanted to see more, you looking at /commits.php instead.
Now it’s going away. First with a redirect to / – after a few weeks of that, it’ll be removed from the code entirely.