file-roller doesn't seem to provide any way to show a zipfile's comment.
In particular, some zipfiles have a password and put that password in
the zipfile's comment, to bypass broken mail filters that silently
discard any zipfile containing an executable.  Without the ability to
show the zipfile's comment, this won't work with file-roller.  unzip on
the command line will show the comment when listing or extracting the
executable, and in particular will show the comment right before asking
for the password.  Please consider showing the zipfile's comment in the
password prompt, at a minimum.

Thanks,
Josh Triplett