It's FOSS - https://itsfoss.com/ocs-store/
Brief: OCS Store allows you to search and install various Linux software, themes, icons etc that you might not even find in your distribution’s software center.
One of the biggest selling points of desktop Linux, for me, is the centralized software distribution system. Ubuntu has Apt, Arch Linux has Pacman and Fedora’s got RPM. This centralized distribution means an increased stability, a superior integration between the apps and the operating system, and an enhanced security factor.