Kalev Lember authored Apr 19, 2019 and Richard Hughes committed May 02, 2019

This allows plugins to control if apps are discoverable or not.

Discoverable here means that they get hidden from search results and
category views, unless they are already installed. This makes it
possible to launch and remove and update already installed apps, but
hides them otherwise.

This is going to be used in the rpm-ostree plugin to hide package-based
desktop apps on Fedora Silverblue and only show flatpak apps by default.