(wondering whether I need to fork and modify some older third-party modules that I'm using that include the outdated "master/slave" terminology)

I believe it should ignore third party modules in the proper folder structure.

@Anish: At the moment it doesn't ignore any documentation. However, I suggest you should open an issue here: https://github.com/efabless/open_mpw_precheck/issues, so we could follow up on this and eventually implement it.