World Space Empties
Bakes and constrains your bones animation into new World Space Empties, this is very similiar to World Space Controls. However it bakes to empties, instead of a control rig. Since Blender 4.4 it will bake all the empties into the same action with different slots for each selection. Before 4.3 it would just bake it all to separate actions.
Empties can have some advantage over World space controls, for example it's possible to use proportional editing with empties while it's not possible with bones, since proportional editing is currently working only with objects.
Type
There are two types of World Space Empties.
Copy Transforms
Is a basic standard world space control. It copies all the transforms - location, rotation and scale to the new World Space Control so they will both at the same position, and constrain the original bones to the Temp controls, using Transform constraints.
Track Target
This creates a target for the selected controls in world space. The selected controls are being tracked using damped track constraint and pointing always towards the world space controls.
Axis
Select on which axis the Track target control should be added, X Y and Z or in Negative axes of -X, -Y and -Z
Offset
Sets the distance from the original bone. Value of 1 on the Y axis, would be normally created at the tail of the bone.
Tip
It is recommened to give enough offset from the original bone, so that it doesn't flip the bone when it's too close.
Twist
Adds a twist control to the Track target controls. The twist is being controlled using the Temp Control rotation of the twist axis, The rest is being controlled by the Track Target control position. Twist is using copy rotation constraints with helper bones to control the twist rotation on the original bone
Example
Creating overlap and tail motion quickly using world space empties.
In Blender 4.4 all the empties are baked into a single action with a slot for each empty
Smartbake
Smartbake works only with Keyframe Range. It keeps the original keyframes count and position from the original bones, instead of baking and creating keyframes on every frame. Smartbake will also recalculate the handles between the keyframes, trying to match the values inbetween
Smart Bake in World Space
Since the new controls are in a world space they can behave different with the same keyframes positions. Depends on the animation, but in most cases it is recommended to keep this option turned off, and bake every frame for world space controls, use smart bake only when baking back into the original rig.
Rotation Mode
Select either to preserve your current rotation order, or to use a different one. You can always convert it later also using the convert rotation tool.
Constraint bones to Ctrls
contstrain the original selected bones back to the empties. Turned on by default
Filters 
Filter specific attributes that you don't want the empties to control. The original bones will be constrained only with the axes that are not filtered.
Only Rotation channels available for Track Target
Track target controls are always influencing only the rotation channels. Therefore when using track target only rotation channels will be baked and available to filter.
When filtering the same axis that is being tracked, then the twist option will be cancelled.
Note
Track target, specifically the twist, works better with World Space Controls, since they are using some helpers bones to convert the twist to local.
Add Extra Child Ctrls
adds an extra empty as a child of the Baked empties. This gives an extra layered control over the temp controls baked animation. the original controls are eventually constrained to the child controls
Add Root Ctrl
Adding an extra root bone for all the controls. It can be based on an object position or another bone. When using a bone the parent control will also bake the animation from the sampled bone. If no bone nor object is selected, then the parent will be added at the 3D cursor position. Root Ctrl can be used either as a temporary pivot, or for working in a different space then world space (for example camera space) or for changing root motion. It's also usefull when using temp ctrls on a cyclic animation, and the original root moves forward. Using the original root as a reference root. Will recreate the movement from the original root and use it's extrapolation