Not all views show software providers for duplicate app listings
When an app offered by multiple sources is shown in the "Search" view of Gnome Software, then the provider for each version of the app is conveniently shown:
However, this is not done for results in the Overview search:
It isn't done for results in category listings either (note the "duplicate" listings for VLC and Ardour):
This is particularly relevant for apps offered in both Flatpak and non-Flatpak versions.