Doesnt's version of the split (the only one that works outside of the Emerald battle engine upgrade) was made by porting a Japanese patch to an English copy of the game, so there's no proper "source" available for it. If you really wanted to see exactly which bytes it changes, you could apply the patch to a ROM and then compare it to an unpatched ROM using a hex editor, which will show you the modified bytes.
You could also read which bytes the patch changes using
this information on the ips file format.