"Visual Studio Express 2013 for Windows" allows me to compile debug, release or master. While the difference between debug and release is known, I've never heard of a master compilation option. What does it do different from release?
The "master" configuration is from Unity, as you stated in your comment and it is used to submit your app to the Store and to remove profiler support.
There are three build configurations you can choose from. Debug should obviously be used to debug your scripts. Release optimizes code for better performance. Master configuration build should be used to submit your app to the Store. It has profiler support stripped out.
For more information, see Building and deploying a Unity Visual Studio solution (HoloLens)