I installed regular
gnome-software to be able to install Flatpaks as well. Right after I did that, all was fine: I could see both "Software" and "Ubuntu software" in the launcher overview and launch either of them.
However, after a restart, I could no longer see Ubuntu Software, and installed Snaps weren't present in the menu anymore either. I have since uninstalled gnome-software, un- and re-installed both Ubuntu Software (
snap remove snap-store and
snap install snap-store) and the Snap app I'm testing with, and restarted, but I still can't see them.
Why did that happen?
As requested by pomsky:
$ ls /var/lib/snapd/desktop/applications/ chromium_chromium.desktop gnome-system-monitor_gnome-system-monitor.desktop keepassxc_keepassxc.desktop mimeinfo.cache signal-desktop_signal-desktop.desktop skype_skypeforlinux.desktop snap-store_snap-store.desktop spotify_spotify.desktop ubports-installer_ubports-installer.desktop
$ echo $XDG_DATA_DIRS /home/vincent/.local/share/flatpak/exports/share/:/var/lib/flatpak/exports/share/:/usr/local/share/:/usr/share/