Olav Vitters created an issue:
I noticed that MirrorBrain hasn't seen much development since 2015 or so. It depends on Python2 instead of Python3. As a consequence of removing Python2, Fedora dropped the MirrorBrain package. This will likely mean you won't get it to work in the next RHEL. Seems often MirrorBrain is replaced by Mirrormanager2, something that Fedora infrastructure is maintaining. I haven't looked into MirrorManager2 at all, not sure if it does the same or not.
Suggest to add the MirrorBrain problem in a roadmap somewhere. It's not urgent now, might be once you need to switch RHEL versions.