Board Thread:Suggestions forum/@comment-33570186-20171105075418/@comment-25841881-20171106231325

The submods made for the mod are basically just texture packs. They change no code, only assets.. And about your actual question:

You don't obtain source files for the mod. The only distributed mod files are the ones contained in the compiled, finished product.. Of course, you could spend a few weeks manually reconstructing the mod by decompiling it and then correcting method and variable names. Except for the most part, you're better off doing something which he has given approval for: Recreating individual features inspired by the mod. Those can be tinkered with as you see fit.