Burger Identity Manager od Cuchaz Interactive

Burger identities are portable identities you can use on the internet.
For more information about portable identities, see:
https://codeberg.org/cuchazinteractive/burgerid

This add-on lets you create, import, export, and manage your Burger identities in the browser.

This browser extension also lets other browser apps use your identity
to perform actions inside those apps. With your permission first, of
course.