The VLW contains all the layers used by Assura in the drc file. Look at this file and you'll understand.
It is usefull when you don't understand an error.
It is also usefull to create your own LVS or DRC file.
VLW is the View Layer Window which appears when you are trying to view your DRC results.The VLW controls the verification colors you display on your screen.
This window displays layers used by assura. The colors in VLW are assigned by assura and may not be same as the original layout.