Digital Audio Workstation. Things like Cakewalk Sonar (which is what I use), Cubase, Ableton, Propellerheads Reason, etc.
So, Guitar Pro is really aimed then at guitarists that might want to demo stuff or write material that they will later properly record? Rather than something that will be used to make a complete track by itself.
The spidey sense started tingling when I saw "Mastering" on the list of tech specs. Since Mastering happens after a track is fully complete/mixed I wondered if they were aiming Guitar Pro as a full weight DAW