…that you can record and play back actions?
As an example, crate a MIDI track and record some movements of a dial or fader from your MIDI controller. Then, set that MIDI tracks’ output to Virtual MIDI 2. Now in “Actions and Shortcuts”, add a “Volume” item in the “Channels” category with the controller you were using and MIDI input VM In 2.
In fact, the Virtual MIDI ports are MIDI cables; whatever you send to VM Out 2 will appear at VM In 2 (likewise for VM i/o 1). You can use this for all kinds of MIDI routing tricks.