gnutls-cli-debug should test whether RSA key exchange is enabled
RSA key exchange is on the way out. It also represents an additional risk to a server due to things like ROBOT. It would be handy to know whether a web site has disabled RSA key exchange entirely.
I'm envisioning a new line in gnutls-cli-debug
output that shows
RSA key exchange supported... yes
(or no
, in the legacy-free case).