It's a Web app installer. You can add pwa's with the help of this app.
This is perfect. It's a shame it doesn't have an explanatory name or a description. Let me describe, have you ever wanted a pwa like app on your phone like minecraft wiki and when you try to add it to homescreen, it acts as a normal tab in the browser. No sandboxing, no fullscreen, tabs get riled up while you search for your minecraft crafting recipes. This happens because Minecraft wiki website doesn't have a manifest which is required to tell the browser to treat is a web app. This app solves that problem.