The wild cat species which is the the wild cat part of the purebred, wildcat hybrid, domestic cat called the Bengal cat is the Asiatic leopard cat; sometimes called the Asian leopard cat or simply the leopard cat.
Asiatic leopard cat is fiercely independent
You can see this cat in the photographs below where he or she is being treated by a rescue centre in Asia. It is very unusual to see such a potentially fierce, small wild cat wearing an Elizabethan collar after treatment. He seems to be quite passive and co-operative but this species of small wild cat is known to be very much the opposite.
There have been attempts to domesticate them but to the best of my knowledge they have failed. I remember a cat lover keeping one or two of these wild cats in an enclosure at his home because it was impossible to domesticate them and treat them as domestic cats. They are fiercely independent. Of all the small wildcats, it could be argued that the leopard cat is the least likely candidate to be domesticated. Other small cats like the margay are more suited but there are no margay hybrids in the domestic cat marketplace (thankfully).
It is said that the Asiatic leopard cat is one of the least likely to be domesticated which is intriguing because this species was chosen as the wild cat half of the wildcat hybrid called the Bengal. It could be argued that the foundation breeders (Jean Mill and associates) could have chosen a more suitable wild cat species to be the foundation wild cat for this breed.