The Animations page of the Scene Settings dialog:

Mesh Animations

• Skeleton Animation Sampling - The default rate or time interval used to sample the skeleton's animation during export.
• Vertex Animation Sampling - The default rate or time interval used to sample the mesh's animation during export.

Node Animations

• Node Animation Sampling - The default rate or time interval used to sample the node's animation during export.
• Interpolation - The interpolation method used to calculate in-between node animation frames at run-time.
• Rotation Interpolation - The interpolation method used to calculate in-between node animation rotation frames at run-time.