Are logos primitives or subfiles?

[Vincent Messenet]

There are also other (sub-)parts which are worth documenting in a kind of prim-ref, like
- screws
- Batteries
etc.

I agree with the subfile approach with a documentation similar to prim-ref. I also add to the list:
- Bottom of stickers (e.g. https://library.ldraw.org/tracker/28343)