Sorry too much the newbie on this sort of thing ... I need a little more directions to understand what "FML/Forge" is refering to. I did try to figure that out, really - Google searches and hunting around the source classes in MCP, looking at the tutorials on this website, searching this website. I haven't found anything yet.
P.S. Understood your answer to my principle question about why Forge modifies the EntityOcelot class. As a player who likes mods, I understand only too well that mods that modify base classes are a pain in the ass as far as compatibility with other mods is concerned. But modifying base classes is the easiet mods to make and I haven't yet learned how to make my own mods in any other way. I would in no way dispute that a mod like Forge should have priority with regards to base class modifications.