That’s not at all what I observed. It was forked at 2.6.32 and then new stable versions were merged in and conflicts resolved by hand. Many many many bugs were not properly fixed, and the difference between this kernel and a real 5.10.66 is larger than between 5.10 and 5.10.66. When I first tried to forward-port this kernel to more recent 5.10, I got many conflicts in important bug fixes that couldn’t be resolved because other prior important fixes had simply been dropped as the result of attempts to resolve merge conflicts in the past.
I’m not judging the people who did that, I know for having been in that positoin that it’s extremely difficult to deal with conflicts in the kernel. But it’s also criminal to maintain a fork for that long a time with only merges, because merges hide mistakes forever by claiming that the entirety of the merged kernel is present there while it’s not, it’s only the result of a manual merge that’s in. BSP kernels ought to be rebased on new major branches. For sure that’s more work for chip vendors, but their efforts would be lowered if they invested the same time trying to upstream more stuff, and their lack of care has for consequences that the claimed 5.10.66 doesn’t have all the fixes that the real 5.10.66 has. That’s just a random piece of shit that nobody knows what’s inside.