How to identify whether an app is a snap or a flatpak or a native app on my computer?

While I generally appreciate the new universal software package approaches like snap or flatpak, I started to feel uncomfortable concerning how to actually tell whether an app installed on my system (16.04 LTS Unity) is a snap app or a flatpak app or even a native app.

To me, it becomes annoying to have an app installed twice or even three times. The 'Dash' search doesn't tell you which one is which. Neither does the Gnome / Ubuntu software center. So, how can I decide which version to remove in order to keep the system as clean as possible?

GNOME Software does indeed tell you if something is a deb, snap or flatpak. If you click on an application and then scroll down past the screenshots you'll see the origin of the software was either from the Ubuntu archive, snapstore or flathub.