Most of the time you made any changes to the core files on how serums worked it didnt take effect until NEXT game. The game still builds its internal arrays of info based on those. Some things could change mid game, like effects, after slapping a new copy of a given effect, but most of the time, anything major resulted in it not working until new game.
Now for the most part.. the py and rpy files are not much different. Small syntax changes, but otherwise the same for the most part. I think the downloaded "full" editions are packed/archived, hence why you cant find anything. Else.. everything is there, maybe moved around a bit to be better sorted. Just look around in the git site.
I pull directly from the git for all the loose files (on develop so i play bleeding edge and iv gotten used to restarts).
Also depending on what you are using for indexing your searches you may need to add .py files into the index.
I just use the base windows index search myself for quick basic stuff, and had to go manually add .py files in the advanced settings and make sure to set "plain text filter". . So i start with a general search term, get the search results, open up all of those in notepad++ and do a full all file search there. Its a bit multi setup but it works to get me what i want.
Also since using a local git sync, i can just edit my copy, merge in anything from the main site, and get a change log for everything.