He's a mix. Thuringer is more a rare breed of rabbit over in Europe, and would be even more extremely rare to find here in the US as it's not a recognized show breed here. Also, you can really only know specific breeds if you get a specific breed from a reputable breeder, or sometimes if a rabbit has very distinctive characteristics of a specific breed. But even then it won't necessarily mean it's 'purebred'. But also, purebred in rabbits isn't a true distinction itself, as most rabbit breeds now, have come about by the crossbreeding of the different domestic breeds that originated from Europe.
If I were to hazard a guess, he could have some lionhead in him. That's the breed to most likely cause that tuft of fur on the top of the head. Then if his ears lop, he probably has holland or mini lop. And I believe the color is called black tort. So black tort lionlop mix would be the most likely combo here in the US.
When you google images for lionlop, you'll see a lot of images of rabbits that are much more fluffy and different looking than your rabbit, but that's just because the different traits that emerge from cross breeding can be unpredictable. When rabbits are cross bred, breeders are looking for specific traits that emerge in the offspring, and when those offspring have the traits a breeder wants to encourage, those will be the ones that are bred for those traits. But that doesn't mean the other kits in the same litter, will all have the same traits that emerge from the cross breeding. They all can exhibit the different parts of the breed traits that the parents have.
