Hydrolase that can remove 'Lys-48'-linked conjugated ubiquitin from proteins. Can also bind to polyubiquitin chains of different linkage types, including 'Lys-6', 'Lys-11', 'Lys-29', 'Lys-33' and 'Lys-63'. May play a regulatory role at the level of protein turnover. 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). Belongs to the MINDY deubiquitinase family. FAM63 subfamily.