They have their own kernel as can be seen here: https://i.imgur.com/jP6Pdvq.png https://i.imgur.com/jP6Pdvq.png Also if you look at the diffstat you can see t

They have their own kernel as can be seen here: https://i.imgur.com/jP6Pdvq.png https://i.imgur.com/jP6Pdvq.png Also if you look at the diffstat you can see that there were a number of changes here: https://i.imgur.com/J2em78v.png https://i.imgur.com/J2em78v.png It may be align with the majority of the kernel, but these patches exist in every version of the kernel that is released by Arch. What else could that be called aside from maintaining your own kernel? These changes are extremely small within scope which is the nature of Arch, but they still exist. A more hands-on distro will see many more changes than Arch, naturally. However, as evidenced from the above you can see that Arch does have it's own kernel and I cited Arch as an example because it strives so hard to maintain 1:1 with upstream. Btw, I use Arch.