Key Times shows the frame numbers along a displayed animation trajectory. Key times correspond to the settings in Time Configuration for Frames or SMPTE. By default, key times are shown as frame numbers.
Procedures
To display trajectory time values in the viewport:
- Select an object with animation.
- On the
Display panel 
Display Properties rollout, turn on Trajectory.
Tip: If the rollout controls are unavailable, right-click the object in the active viewport, choose Object Properties, and in the Display Properties group, click By Layer to change to By Object. This will make the Trajectory option become available. - Turn on Show Key Times.
The time values are displayed as white numbers along the trajectory. They remain displayed in red when the animated object is deselected.
Keyframes with frame number shown on a trajectory.