it would be nice to know easily beforehand whether a module has a direct, or indirect dependency upon XS or C

Backe in ye olde darke ages, such information was provided by the DSLIP code of a module, as it appears on The Module List.

These days, that list has fallen into a state of disuse, and dslip has fallen by the wayside. Many authors are unaware of its existence, never mind your average Perl user who just wants to get the job done.

The current feeling is to expand the META.yml file that should exist in a reasonbly well maintained module, to provide a revamped XXI century version of the information that used to appear in the old DSLIP codes. There was a thread recently on the matter on p5p (I think, or maybe module-authors) although no firm conclusion was reached. The options for Support were considered especially outdated.