Ok, fair question. Let's look at the commit history for MrMC fork.
There are three places, my repo (davilla), the mrmc repo and and untouched branch of the initial MrMC public.
https://github.com/davilla/mrmc
https://github.com/MrMC/mrmc
https://github.com/MrMC/mrmc/tree/20151129-master
The reason for three is MrMC started in mine under a different name, changed to MrMC and later got github to transfer master to MrMC repo, then back synced mine to it. The branch is an archive of original public commits because we had a sync snafu between it and our private repo and had to force push to clear it. Before anyone starts bitching about a private repo, VLC does the exact same thing for it's iOS and tvOS development.
Aug 25, 2015
MrMC fork started here, soon after I left Pivos. Amet and I decided to fork and go off in a different direction.
https://github.com/MrMC/mrmc/commit/6dc1...3fbc311b3c
Aug 30, 2015
Python was ripped out here
https://github.com/MrMC/mrmc/commit/c06c...72dbef0207
Sep 4, 2015, MrMC created on github, prior to that, it was located in
https://github.com/davilla/mrmc
Sep 8, 2015
1st hint of ATV4 support is here
https://github.com/MrMC/mrmc/commit/a5d5...6adc039fac
Sep 9, 2015
ATV4 announced by Apple
http://www.apple.com/pr/library/2015/09/...le-TV.html
Sep 18, 2015
1st move to actually support ATV4 is here
https://github.com/MrMC/mrmc/commit/3d5f...3116d2517d
MrMC on ATV4 came alive sometime in November and was into Apple Store in December.
The ATV4 was never the initial target for MrMC fork, we did not even know about the ATV4 until Sept 8th. Even my spies did not know it existed until then.
Then amet and I worked like crazy to add support for it. Python/addons were already long gone.
It's clear to see, MrMC forked, a ton of refactoring work including the removal of python/addons. ATV4 popped out, we jumped on it. Sure it was a very short timeline but just look over the hundred+ commits and make your own judgement.