ActionTokenHandler examples

Other than the docs https://www.keycloak.org/docs/latest/server_development/#_action_token_spi, is anyone aware of concrete examples of custom ActionToken/ActionTokenHandler implementations?

I implemented it once for a customer as a kind of magic login link.
And I’ve seen it has been used as custom registration thing, where the user was “registered” through a third party and has to “finish” this registration. There was also an action token link used.

But sorry, no public code examples available.