What are they:

Window presets are files that can be created with WinDVD Tweaker to store certain Window Sizes. Although the automatic calculation of window sizes should be enough for most people this facility is here incase someone needs it. The files carry the file extension ".win" and can be loaded from within WinDVD Tweaker or by double clicking them from outside WinDVD Tweaker.

All window presets that are found in the WinDVD Tweaker folder, will be added to the list in the program so you can select whatever one you like from the drop down list.

Extension:

.win