From Better Posters I learned about the idea and that there is a serious effort to create such a registry: ConfIDent.

But is it ready for prime-time?

• Terms of use only available in German, as far as I can tell.
• Account creation flow involves manually requesting an account, but it is not clear to me who is behind this service. Strike that, the Imprint makes it clear: the Ministry for Science and Culture of Lower Saxony, Germany.

Very cool :-)

Here's my modest profile, for example.

Via https://discuss.systems/@ricci/113684446286253550

Explore our hand-picked collection of out-of-copyright works, free for all to browse, download, and reuse. This is a living database with new images added every week.

Via https://mastodon.social/@publicdomainrev/113794180924217390