It is actually, on the system-settings side. It's hidden because unity8 doesn't respect the setting. Launch system-settings with USS_SHOW_ALL_UI=1 in its environment if you want to see that.
The setting to look at is: gsettings: com.ubuntu.touch.system rotation-lock
Adding unity8 to this bug, because surprisingly I cannot find another one.
It is actually, on the system-settings side. It's hidden because unity8 doesn't respect the setting. Launch system-settings with USS_SHOW_ALL_UI=1 in its environment if you want to see that.
The setting to look at is: gsettings: com.ubuntu. touch.system rotation-lock
Adding unity8 to this bug, because surprisingly I cannot find another one.