bipface said:
what does it do?

Its a kali linux subsystem mod for windows 10 OS. Using kex2.0 it basicly runs kali linux on top of the win10 environment so you can enjoy a win OS as usual while doing infosec in the same desktop istead of switching to pure kali linux only.

See: https://www.kali.org/ && https://www.kali.org/news/win-kex-version-2-0/
For more info