This version adds mouse support. The purpose is not to actually play with the mouse, but to play with the Sinden Light gun which emulates the mouse. The Sinden Light Gun has many advantages over a laser, such as not needing a separate webcam, not needing calibration, running during the day at full brightness, and it's cheap relative to the other accessories. The disadvantage is you are not using your real gun, which limits training value, and it only works on the Windows version of IGR.
See https://interactivegunrange.com/sindenwithigr/ for details on how to set this up.