After pushing out over-the-air updates to Android 5.1 to AT&T and Sprint HTC One M9's here in the US, the manufacturer has now posted the open source kernel files. It has also shared fresh builds for the same phone in Taiwan. You can find them over at the HTC developer center. Downloads come in at over 500MB.

HTCOneM9KernelFiles

These files come after their counterparts for the unlocked One M9. They enable ROM creators to better support HTC's flagship, and they can be a help to other developers as well. As for everyone else, there's nothing much to see here.