On android the ususal way to close an app is to swipe, but on android you can exit the app by swiping but it doesn't closes the app as if you do it in the menu -> close.
If you just swipe the app then all the open tabs are stored in the browser. It's not very great for those of us that is used and liked to have a cleard browser every time we open the browser.
Closing the app by swipe should close the app the same way a closing the app in the menu -> close does