Exosulfatase involved in the degradation of the glycosaminoglycans (GAGs) chondroitin sulfate (CS), dermatan sulfate (DS) and heparan sulfate (HS). 2-O-sulfatase active on unsaturated non-reducing end hexuronate units. Has a slight preference for HS-derived structures (PubMed:25002587). GAG-specific sulfatases play a key role in the persistence of the major human gut symbiont B.thetaiotaomicron in the host gastrointestinal tract (PubMed:25002587). The conversion to 3-oxoalanine (also known as C-formylglycine, FGly), of a serine or cysteine residue in prokaryotes and of a cysteine residue in eukaryotes, is critical for catalytic activity. Belongs to the sulfatase family.