Legacy CA's as tests?

Fedora seems to be close to disabling some old CA's (with e.g. 1024 bit RSA keys etc.), see

https://fedoraproject.org/wiki/CA-Certificates 

and 

https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/7BEOPFFBLCGDLUL4SIVTJG2YXX4OKRE6/

If there still are sites using certs with those CA's, there could be a check that checks whether they're still in use or not.
