Lots of the ARM-related changes are cleanups/modernization of code that the Apple support uses, e.g. https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/...

Cyclades removal was about dead, unmaintained code: https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/...

This is a 60-commit branch, which had to decouple a lot of different bits of ARM-platform code. Specifically, they use a totally different boot method, have a weird and special power-management system, and other stuff I don't know. See this article: https://asahilinux.org/2021/03/progress-report-january-febru...