rel values describe the link itself. author, license, nofollow and tag are link types in the HTML Standard; enclosure marks a downloadable attachment such as a podcast file. Parsers collect them page-wide rather than inside an h-* object.
<a rel="author" href="/about">Erin Smith</a>
<a rel="license" href="https://creativecommons.org/licenses/by/4.0/">CC BY 4.0</a>
<a rel="tag" href="/tags/html">html</a>
<a rel="enclosure" href="/talk.mp4">Download the talk</a>
<a rel="nofollow ugc" href="https://spam.example/">A commenter's link</a>
<a rel="me" href="https://social.example/@erin">Mastodon</a>
<a rel="friend met co-worker" href="https://josh.example/">Josh</a>{"rels": {"author": ["https://example.com/about"],
"license": ["https://creativecommons.org/licenses/by/4.0/"],
"tag": ["https://example.com/tags/html"], "enclosure": ["https://example.com/talk.mp4"],
"nofollow": ["https://spam.example/"], "ugc": ["https://spam.example/"],
"me": ["https://social.example/@erin"], "friend": ["https://josh.example/"],
"met": ["https://josh.example/"], "co-worker": ["https://josh.example/"]}}Only rels is shown; rel-urls lists the same links by URL. Google's handling of nofollow and ugc is in nofollow, sponsored and ugc.