Responsible for the degradation of GM2 gangliosides, and a variety of other molecules containing terminal N-acetyl hexosamines. This enzyme plays a role during the slug stage of development in the maintenance of pseudoplasmodia of normal size. Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. Dimer. The N-terminus is blocked. N-glycosylated. Belongs to the glycosyl hydrolase 20 family.