"foreign" docker hub triggers

I am referencing to https://support.tutum.co/support/solutions/articles/5000513815-triggers .
I created such a trigger for a repository which is not my own, some months ago.
e.g. my tutum service “phpmyadmin” has a trigger which is called by docker hub whenever a new image of phpmyadmin is pushed.

This is still working fine and triggered from time to time (I see this in the service timeline).

My problem: I cannot find the place to enter or change a trigger in docker hub anymore.
This seems only to be possible in my own docker repositories.

Where can I enter triggers in other people’s repos?

Thank you very much.