Yeah the files are organized into a directory hierarchy, pretty cool tech! :-)

And there are great tools for exploring directories of files, my current favorite is dolphin with two or three panes.

you can run windirstat (or similar tool) on a checkout to get an idea

Yeah, I guess this is the answer. When I posted the question I had this[1] in mind, and was thinking of something like that with simplified labels maybe. But I guess the file structure is so organized it would explain itself to anyone interested in this kind of thing.

[1] https://upload.wikimedia.org/wikipedia/commons/d/d5/GNOME_Di...

Wikipedia has a graph showing high-level breakdown of the kernel tree, and the size of the components[1]

[1] https://en.wikipedia.org/wiki/Linux_kernel#/media/File:Sanke...