Presumably the recipe is not public, but I'm sure people have figured some of it out. One book I have mentions saffron as a prominent inclusion.

I ask because when I first tasted Bénédictine, I recognized the flavor -- or the smell, at least -- as something familiar but nothing specific came to mind. It didn't taste like any food I'd had before. I finally made the connection tonight: Bénédictine has a very similar aroma to witch-hazel. Witch-hazel itself smells very nice, almost sweet, but I haven't found any information online about it being used as a flavoring or food, so the similar aromas may just be coincidental.