gnome-app-install | dummy upgrade package for gnome-app-install -> software-center | Mehr ...
This is a transitional package so that gnome-app-install users get software-center on upgrades. It can be safely removed.
software-center | Utility for browsing, installing, and removing applications | Mehr ...
The Software Center lets you browse and install thousands of free applications. You can view available applications by category, or search quickly by name or description. You can also examine the applications already installed, and remove those you no longer need. . To install or remove software using the Center, you need administrator access on the computer.