How do i get this for PC and what does it do?

It was a skip in the game which allowed us to skip the whole "Weasley After Class" quest. Basically, you would hit the button to start the mission but then go to the map and fast travel before the cutscene started. The quest would instantly pass. It was patched by the developers in an update so we use the variable to identify whether you are running on the latest version or an older one.

Thank you!