This is a simple redirection service for Mozilla's old code-review system, MozReview. The purpose of this service is to redirect old MozReview links to useful, related URLs.
Currently, this service provides the following redirects:
/r/<id>/redirect to their associated bug on BMO.
/r/<id>/diff/[<revision>/]redirect to the associated commit in the review-repo archive. Note that, at the moment, all revisions of a given diff redirect to the last (i.e. most recent) diff. You can find older diffs by searching the archive for the