2/ …looked at the mainline changes backported to the 6.9.y series and then checked if they were referred to in a Fixes: tag found in another mainline change committed within 9 weeks (e.g. one cycle).
There the -rc1 commits did not stand out.
The only problem thus was the number of changes, which of course makes it more likely for users to be affected by regression.
Screenshot in the first toot of the thread if from https://lwn.net/Articles/863505/