This is a really excellent writeup. It's light on technical details, exploring much more the motivations behind why things have evolved the way they have. But

This is a really excellent writeup. It's light on technical details, exploring much more the motivations behind why things have evolved the way they have. But, Bram does show the project file layout with brief descriptions of what each file contains, pertaining to Vim. Very good. Informative, interesting and maybe even a little motivational.