That's not very precise. :) Many of my patches from my kernel get pulled to "pine64" kernel, including those that are not mainlinable. Distros that care about mainline just use Linus's tree already.

There are not many reasons not to use my kernel tree for Pinephone. I actually had reports from users that my multi-distro image that uses my kernel for 13 different pinephone distributions makes some distros run better.

I suspect that distro maintainers just think that pine64 community gitlab is somehow more official than any other pinephone kernel developer's tree on the internet, just from the name.