The signed pacman repository the Omarchy Mobile Market installs from: apps built from the AUR and tested on a phone-sized screen, and the moarchy-apps Quickshell apps.
Nothing to set up: on Omarchy Mobile the Market installs from here after the phone's PIN, and its package adds this repository and trusts its key. (App Finder installs the same apps from the AUR.)
Key fingerprint: 3CA83612E7F3108F442006B418305B893569BAD3