Color genetics

[Jennin Lauma]

Where did the Saarloos inherit the white, open masks?



Or sometimes occuring white tail & toe tips?

Also the "forest brown" colour makes me wonder...
-Is it the same gene as the liver GSD, and only appears in SWH together with the "agouti" wolf colouring (with the lighter underparts of the body & light undercoat)?
It is definetly a liver gene that causes it, because of the lack of black whatsoever, but did it come from the GSD or perhaps from some other breed mixed in?

I am greatfull for any answers! Thanks in advance!