The Rotation Timeline is the third timeline (green colored horizontal bar) in the Keyframer and controls where and how an Actor will rotate or be aligned from keyframe to keyframe.
All settings are grouped in a single dialog which will appear when a timeline is created or edited. The dialog shows the timeline extent, the alignment (in degrees) in three axes of the Actor, and the Rotation Type.
The Delete button deletes the rotation timeline.
The Cut button deletes the current timeline and shifts all later rotation timelines back in time to fill the gap.
The Copy button copies the rotation characteristics of another Actor.