Many tests in trio/_tests/test_dtls.py fail with "DeprecationWarning:
Attempting to mutate a Context after a Connection was created. In the future,
this will raise an exception", this is a new warning added in python3-openssl
25.1.0-1.

I've tried to update the package to 0.30.0 (I don't need it but I wanted to
remove the last revdep of python3-sphinx-hoverxref; my work is pushed to salsa)
and noticed this problem. I've confirmed that it happens with the sid version
too. I can't see any upstream bugs about this.