I suppose it would be possible to extend the CPAN META.json/META.yml file. Maybe something like "supported_platforms" and/or "unsupported_platforms". Precisely how you define a "platform" seems an awkward problem though, e.g. "Windows" versus "Windows Vista"; "Unix" versus "Linux" versus "AIX 6.1" versus "AIX 5.3" and so on. Also, Perl may be ported to new platforms after a module is released.