As this is a discussion forum and this is quite a straight forward request, perhaps it's better to issue an issue at the certbot GitHub page: github.com/certbot/certbot/issues
How would you have that in mind? Use the certificate of said site? Or should it also work for a site without HTTPS?
Oeehh, sorry, missed that. Forgot that section even existed, although certbot strictly is an EFF project nowadays (Trying to talk things straight for me, obviously ;))