The Mastadon profile settings allow adding URLs to the profile, and it includes this:
Verification
You can verify yourself as the owner of the links in your profile metadata. For that, the linked website must contain a link back to your Mastodon profile. The link back must have a
rel="me"attribute. The text content of the link does not matter. Here is an example:<a rel="me" href="https://mstdn.ca/@glennj">Mastodon</a>
The feature request
- add Mastadon to “Your social accounts”. The field would validate the format
@handle@server - add a link+img to the external-links, where the link format is
<a rel="me" href="https://server/@handle">as indicated above.