All details here : http://forums.kc-mm.com/index.php?topic=41974.0
Rename the .pac file into FitYoshi or it won't work !
As the title says, this hack makes Yoshi be specialized with grab/throws and they are his best ways to KO an opponent.
Down throw acts like a spike.
All throws have more knockback.
Smash attacks have less knockback.
Neutral B works differently and can heal Yoshi, it depends on the number of grab attacks he made.
New damage system for pummels.
His mouth his bigger when there is an opponent inside (like in smash bros melee).
Autodeath when 999% are reached included.