The trim under the window is just a strip of matte board with wood dowel on top, with X-acto lines again.
If you like the look of cut-outs in your wrappers, you can make them with scissors or an X-Acto knife.
For smaller and more precise shapes, an X-Acto knife is a good choice.
Dig the X-Acto knife into the traced lines and drag it across evenly, keeping the pressure equal all the time.
With the tip of the razor or X-Acto knife, press down on the edges of the design and remove them from the stencil.