This is basically to bake constraints faster, using less keyframes.

The Default bake keys all frames in the bake-range, and also misses some frames when they are not "needed" for the curve. This leaves you with a lot of extra frames.

Using Bake Available, you can offset the animation on your bones/objects, using constraints, while maintaining your keyframe density allowing for further tweaks.

This addon contains 2 buttons.

• 1 go to all the available keyframes for the selected objects+bones and the targets in their available constraints (the eye icon is not muted), then insert keyframes for the "visual" transforms of the selected.
• 2 run the default Bake operator, using Visual Transforms, setting the Start+End frame range at whatever is already available in the selected (or the current frame if only 1 or 0 frames are available).

Bake Available - Caveats: This manually goes through each keyframed-frame for everything selected, which can be slow if you have a lot of objects/bones + keyframes. It does not account for the curves/ in-between-interpolation, meaning the frames between keyframes may not transition as original.

Note: These do not remove constraints, so if you're using an offset type constraint, you have to remove/disable them after bake.