This is for Sense 6 devices like One M7 and M8.
HTC File Manager
Seems to be fixes, and that you can view hidden files etc.
HTC Gallery
In main album view, the album preview image is now animated and shows a little “slideshow” for a while. Not all at the same time (thank something). And various fixes.
HTC Service Pack
Regular fixes, as they never say just what it fixes.