Recognizes and hydrolyzes the peptide bond at the C-terminal Gly of ubiquitin (By similarity). Involved in the processing of poly-ubiquitin precursors as well as that of ubiquitinated proteins (By similarity). Required post-developmentally to restrict the plasticity of epidermal cells, probably by regulating gene expression (PubMed:31088904). Thiol-dependent hydrolysis of ester, thioester, amide, peptide and isopeptide bonds formed by the C-terminal Gly of ubiquitin (a 76-residue protein attached to proteins as an intracellular targeting signal). In pachytene germline cells and oocytes, localizes to chromosomes. Broadly expressed. Expressed in germline. Belongs to the peptidase C19 family.