Agreed. Without flattening, here is a concrete proposal on shortening to
review / discuss / improve:
[Qubes OS Community Forum] --> [Qubes OS] or [Qubes Forum]
[General Discussion] --> [General]
[User Support] --> [Support]
[User Support/Hardware Support] --> [Support/Hardware]
[User Support/Guides] --> [Support/Guides]
[User Support/HCL Reports] --> [Support/HCL]
[User Support/Testing 4.1] --> [Support/Testing 4.1]
[News] --> [News]
[In your language] --> [Local]
[In your language/Deutsch (German)] --> [Local/Deutsch]
[In your language/汉语/漢語 (Chinese)] --> [Local/汉语/漢語]
[In your language/Español (Spanish)] --> [Local/Español]
[Feedback] --> [Feedback]
[Feedback/Forum Feedback] --> [Feedback/Forum]
[Feedback/Website Feedback] --> [Feedback/Website]
Maybe it is possible to only flatten it out in the email headers? So it
would look like this in email only …
[General Discussion] --> [General]
[User Support] --> [Support]
[User Support/Hardware Support] --> [Hardware]
[User Support/Guides] --> [Guides]
[User Support/HCL Reports] --> [HCL]
[User Support/Testing 4.1] --> [Testing 4.1]
[News] --> [News]
[In your language] --> [Local]
[In your language/Deutsch (German)] --> [Deutsch]
[In your language/汉语/漢語 (Chinese)] --> [汉语/漢語]
[In your language/Español (Spanish)] --> [Español]
[Feedback] --> [Feedback]
[Feedback/Forum Feedback] --> [Forum]
[Feedback/Website Feedback] --> [Website]
… basically if there a subcategory, print that one only?