Mari 4.5v2 docs:

Play Controls Toolbar

The Play Controls toolbar and the controls that can be found on it are described in the table below. The Play Controls toolbar allows you to play animations. You can set keyframes, which allows you to paint different textures in different parts of the animation sequence.

Play Controls Toolbar Controls

Control	Type	What it does	Notes
Timeline	timeline	Shows the position of the playhead. Keyframes appear as orange markers in the timeline.
	entry box	Sets the frame range: the start and end frames of the animation.
	button	Adds a keyframe at the current frame.
	button	Removes the selected keyframe.
	button	Moves back a single frame.
	button	Moves back to the beginning of the animation.
	button	Plays the animation.
	button	Stops playing.
	button	Moves forward a single frame.
	entry box, dropdown	Skips to a particular frame. Select the play mode from the dropdown. One of: • Loop - plays the selected frames through, repeating again from the start when it finishes. • Bounce - plays the selected frames through from start to finish, then backwards from the finish to start, and then repeating. • Stop - plays the animation once and then stop. Sets the frame rate.