This file applies a change to the player jumping physics, and alters its pose accordingly if set to do so. The configuration can be applied to all player characters, to a specific character or can be RAM flag dependent.
Details and example on how to set and use the code are found all within the ASM file.
There's a fine piece of code, Blind Devil. However, I'll have to reject because of this glitch (ignore the glitched P-balloon GFX):
As you can see, your code messes up Mario's pose when he gets a balloon. All the other things you mentioned you fixed are working fine; just this glitch and your code is all-ready for approval.