The idea is have a Transform Cage to move, rotate and scale in the 3D viewport (similar to the gizmo that exists for 2D UV editing).
This is will be realy useful for Grease Pencil and 2D animation workflow and is common in other 2D animation programs.
Please, check this video for more info:
*is this just the current scale cage with rotation handles added?
Yes, basically. It would be nice if you grab an edge of the cage you have a skew transform (see the video)
Would the pivot point be used only for rotation or scale as well?
Yes, for all tranformations
Would it be possible not to use this pivot point, and use the 3D cursor instead?
It´s is possible but I think that is more convenient and easy for the user
How this is accessed (As a sub-tool of transform? like scale cage?)
Yes, as a sub-tool of transform