After looking into the release history for gnome-software, I found that the issue might have re-appeared after re-basing gnome-software from version 3.20.1 to the upstream 3.20.5.
-- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-software in Ubuntu. https://bugs.launchpad.net/bugs/1672424 Title: Cannot install Debian files outside of the repositories To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-release-notes/+bug/1672424/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs