What does each component of 'get input motion state' represent?

Hello Everybody!

Could someone please help me understand what data is stored in each of the vector components of the ‘get input motion state’ i.e in Tilt, Acceleration, Gravity, Rotation rate? As far as I know(please correct me if I am wrong!) they are rotation angles around each axis of the device’s ‘transform’ but I don’t know in which order. And why for example the ‘y’ component of Tilt always returns zero( at least when I was playing with it :stuck_out_tongue: ) I would be glad if you guys explain this or point me to an article or even the relevant parts of the engine’s source code where I can examine it for myself

Many thanks!