Component of a deubiquitination module (DUB module) that specifically deubiquinates monoubiquinated histone H2B (H2Bub) (PubMed:29588169, PubMed:30192741). Does not seem to be a component of the TREX-2 complex (PubMed:29588169). Seems to act independently of the SAGA multiprotein complex (PubMed:30192741). The DUB module is responsible for the major H2Bub deubiquitinase activity in Arabidopsis (PubMed:30192741). 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). Component of a deubiquitination module (DUB module) formed by ENY2, SGF11, and UBP22 in Arabidopsis (PubMed:29588169, PubMed:30192741). Interacts directly with SGF11, but not with ENY2 (PubMed:29588169, PubMed:30192741). Displays a rather patchy distribution forming a punctuated pattern in the euchromatin (PubMed:30192741). Does not localize in the heterochromatic chromocenters or nucleolus (PubMed:30192741). Belongs to the peptidase C19 family.