Pose rotation space

I’m working on some shapekey drivers and I’m not understanding something about pose/world/local space?

Why is it that when I rotate this bone 20 degrees on Y that the rotation values are not matching in the properties panel.

Scale and rotation are applied on both the model and the metarig.

Bone has its own coordinate system; Y axis is pointing up in your image. Because bone operates from its own axis, when you manipulate it you need to use Normal coordinate setting to do it.

Ok thanks. I’ll read some on the coordinate system.