This is used to generate everything required for the msvc ros runtime (i.e. roscore, rosmaster, roslaunch, rostopic etc). It does this by ensuring there are executables for the python scripts (ugh, windoze) and also by creating dummy targets so that this can act as a meta-package for getting the runtime built in one shot.
These scripts can't be run without a .py extension on windows and even then, can't be run in the shell without directly calling python first. Alot of the ros architecture expects these to be directly executable, so rather than modifying the whole ros architecture, we sub in executables that indirectly execute the python scripts.
Simply copy one of the existing .exe's and rename it (they are self-calling). More permanently, modify CMakeLists.txt in the src folder.