provide a way to validate CPAN author accounts

This should be mostly trivial, since authors can upload arbitrary files into their personal directory, and that entire directory is mirrored and publicly available (for instance, http://www.cpan.org/authors/id/D/DO/DOY/). One issue that might make this more difficult is that files are immutable - if you want to update a file in your directory, you have to use a different filename each time. A basic versioning scheme should be able to work around this issue though.

I imagine that other repositories (npm, etc) should have similar mechanisms (and this would be a useful feature there too), but I'm not familiar with any of them.

No repository file, test, or entry point is named. Start by defining the CPAN author-account validation scope and how immutable filenames affect versioning; done means an agreed mechanism is specified for validating accounts through publicly mirrored author directories.

Written by the indexing model from the issue text.