[vfclists]

And what happens when these castle_xx files have to be combined with files from other libraries?

This goes a long way into avoid namespace conflicts.

[dkersten]

Do they need that? If not you’re using a hypothetical situation that likely will never occur to excuse a bad decision (see YAGNI). In my 24 years of programming, I’ve never needed to do this in any way where this naming would have helped me (a very occasional single prefixed file sure, but an entire project, never).