Oh! Forgot. Android has three buttons; ||| , □ and < . This back button ( < ) universally among every app out there lets you exit the app back to your homescreen once you reached the top of the apphierachy. In damus, it just does nothing. First time i have encountered that in any app. Technically i can still use the dedicated □ button, but i am not going to learn new controlls because one app decides to be an outlier.