Similar to its rel=me checking support (validator), IndieWebify should support parsing, checking, and advising how to improve any rel=author (https://microformats.org/wiki/rel-author) links found on a page.

IndieWebify should look for and check both:

<a rel="author" href="https://…">

and

<link rel="author" href="https://…">

tags, and display a list of all of them found on a particular page, along with any additional information about each one (e.g. type=, title=, and hreflang= attributes).

Ideally it should also check for a valid representative h-card at the destination of a rel=author link.

This is worth implementing both as its own IndieWebify feature (especially so software & services like Mastodon could test an implementation), and as a building block towards implementing a complete authorship validator (issue #6).