There has been some discussion about adding back button support across Plasma Mobile.
Why it's important:
Generally phones have a lot less real estate to show information, so that means it's likely that an app that is optimized for touch will have multiple views
be it hamburger menu/bottom nav bar or something else.
And that's why you frequently need to go back from the view to the main screen for example
And because every app places back button in a different spot/doesn't have any
it becomes a chore
that's why a universal back button is so important (and present in iOS/android/winPhone)
A software back button can likely just trigger a "mouse back" button press.
Mostly, this comes down to implementation in UI toolkits (Kirigami, maybe propose in GTK?) and applications (ex. angelfish back would go back a webpage).
However, in Android, back presses reach a certain point where there are no actions left to go, and so the shell decides whether or not to switch to the previous app, or go to the homescreen. It is possible that we can propose a spec where an app can report or emit a signal when it has no back actions left, and the shell can hook into that to determine which actions to take.
Some important notes:
# This is not meant to replace back navigation in app just augment it
# It's important to have a consistent way to go back on phones ( see android back button and ios back gesture + windows mobile before it died)
# On android the app is minimized when it can't go back anymore
- Could be done without a spec (using mouse back em), but then it wouldn't know when to minimize
# when back is pressed it sends a mouse back click to the app it. then queries if it can go back though a small spec
# If the app hasn't implemented the spec the back button could either always minimize it or always emulate the back button
# Should probably be done though dbus but could also work in wayland
# it'd definitely have to be long term because apps would now need to have back actions determined