This is a Virtual Controller Keyboard. It sends out MIDI note & control data. The knobs send MIDI control data for controllers 0-7 & the buttons send MIDI control data for controllers 8-15. This is useful for controlling the studio using the Internal MIDI buses and means you could assign several controls to one knob or one button.
The [MIDI] button opens a window to select the MIDI out channel & port. See MIDI Devices & Controls.
The [Cntrl] button opens the MIDI Control editor and allows you to edit all MIDI controls in the studio. See MIDI Devices & Controls.
The MIDI Note On/Off data is sent using the keyboard which can be played by either the mouse or the QWERTY keyboard. The bottom rows starting A & Z do the lowest notes, the row starting Q and 1, the highest. The keyboard is transposed up and down an octave by the +(=) or - keys. If you are connected to a collaboration this MIDI data will be sent to all participants, however the [Net] button allows or stops Note events from being sent.