Comment 6 for bug 1610929

Mir has no knowledge of stages. That is a concept which exists at the higher level in Unity8. However Mir's form factor enumeration would probably need a new entry still. And an API for Unity8 to set it.

Before we go wedging something called "staged" into Mir though, please try to consider a generalised approach that is a superset of the Unity8 design. Since Mir should support other shells. What we call "staged" might be called "tiled" in Mir for example.

So we need a design, but before that we need to be more confident that any change in Mir is really required at all.