This is the WiDI Desktop Application.
WiDI Remote MIDI Controller app for iPhone® and iPad® connects to the desktop application to exchange MIDI messages with your MIDI devices over the network.
The WiDI Desktop Application is a very lightweight program that does not need to perform any kind of installation procedure and do not write files on your computer. Just run it, and it will start to listen to incoming connection from your iPhone® or iPad®.
You can install it on as many Mac as you want.
Multiple WiDI app can connect at the same time to the same Desktop Application, thus allowing multiple control surfaces for the same devices connected to your Mac.
WiDI Remote MIDI Controller App Store page : https://itunes.apple.com/us/app/widi-remote-midi-controller/id1420223879?mt=8
Up to six family members will be able to use this app with Family Sharing enabled.