Bauernbier. Literally “farm” beer, the moniker should only be used by a countryside brewery and usually refers to their flagship brew. In Franconia, they seem to be on the amber to light brown side. So, much like Altfränkisches, more a name (and marketing image) than actual style. They hover around 5%.
Held-Bräu Bauernbier Dunkel in Oberailsfeld is a good example of a classic Dunkles with the brewery using the Bauernbier designation to play up its countryside location as well as point out that this dark brew is their pride and joy. I can see (and taste) why.