.j files only for w/e?

I've been wondering...is the files blizzard.j and common.j only for the w/e..ro does changing stuff in there actually make much difference in normal wc3?

Ive been spending a bit of time studying it and realized that most of blizzard.j is just mentioning the triggers in the w/e and what they do. Altho some of it does relate directly to melee games..as in starting units and positions, but is the rest of it only for triggers?

blizzard.j and common.j and the actual JASS functions used in triggers. They also have definitions of game variables.