Involved in brain restructurization via hormonal control during metamorphosis. Implicated in N-glycan processing. Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. In third instar larval and early pupal brains, expressed in cells sending projections across the interhemispheric junction. In adult brain, expressed in mushroom body, ellipsoid body and pars intercerebralis. Belongs to the glycosyl hydrolase 20 family.