If you have multiple domains, or want your GitHub/GitLab/Codeberg profile to link to something that is not your main website, you can alternatively put one or more URLs in your "bio" field on GitHub, GitLab, and Codeberg. This allows you to use one GitHub/GitLab/Codeberg account to authenticate multiple domains.
If you don't want IndieLogin.com to consider all your rel="me" links as possible authentication options, you can choose which ones specifically by using rel="me authn" instead. This allows you to, for example, only use providers that support two-factor authorization, while still linking to your existing profiles using rel="me".
<a href="https://twitter.com/aaronpk" rel="me">twitter.com/aaronpk</a> <a href="https://github.com/aaronpk" rel="me authn">github.com/aaronpk</a>
If any of your rel="me" links also include authn in the list of rels, then IndieLogin.com will only use the links with authn, and will no longer consider your plain rel="me" links as authentication options.
The same goes for a link to a key: rel="ssh-key authn" or rel="pgpkey authn" keeps it in the list when you use authn.