Fernet Francisco is a brand of fernet distilled in San Francisco, where Fernet-Branca has long been a cult favorite. It's one of a growing number of American craft fernets (buoyed by the rising popularity of amari in general), and is made with a relatively secret collection of "12 hand-picked, local herbs and botanicals," including rhubarb, German chamomile, orange peel, bay leaf, spearmint, peppermint, gentian, and cinnamon. Fernet Francisco is a bit more subtle and drinkable than its legendary cousin, and is certainly growing its own cult following in the Bay Area.
As a category, fernet is generally very bitter, minty, and thanks to the eclectic array of ingredients, displays truly unique flavors all around. It's frequently quaffed with a ginger ale back in San Francisco, in a Fernet and Coke in Argentina, and mixed with soda water in Italy, much like Campari or other amari.