Name: RealMe (rel="me" Link Verification for MediaWiki)
Homepage: https://www.mediawiki.org/wiki/Help:Extension:RealMe
Short description: The RealMe MediaWiki extension allows verifying external links on user pages (and other pages via a config file) using the rel="me" attribute. This enables services like Mastodon to verify the ownership of linked profiles. Keyoxide integration would allow users to verify their MediaWiki user page and link it to their Keyoxide profile.
Optional API documentation URL: N/A (The functionality relies on adding URLs to the MediaWiki user preferences or a config file and then having the RealMe extension output the necessary HTML. There isn't a dedicated API for interacting with this data.) Proofs could be implemented by checking the HTML <head> of the user page for a <link rel="me" href="..."> tag pointing to the Keyoxide profile.