MouselookHandler is an interface addon for the World of Warcraft MMOG that adapts the game controls to enable using mouselook without the RSI-inducing requirement of perpetually pressing a mouse button. This makes the controls resemble those of most action games.

The addon is available on CurseForge and the source code can be found on GitHub. Here’s something someone on CurseForge said about MouselookHandler (any emphasis is copied from the original):

Dude this addon is slicker than a greased up pig in a field of eels.