@seb128 - can you confirm if gpg-keys is needed at all with portals support? If not, this reduces down to just cups-control from what I can see. The current process for auto-connect of cups-control is limited to printing and design applications where printing is part of the expected workflow. As such, Thunderbird does not strictly fit this definition as it is not a printing / design application. However, I tend to agree that printing of emails is a pretty common operation (similar to say printing of web-pages as we grant for chromium) - and so I vote +1 for auto-connect of cups-control for thunderbird myself.