Poly(ADP-ribose) glycohydrolase that degrades poly(ADP- ribose) by hydrolyzing the ribose-ribose bonds present in poly(ADP- ribose) (PubMed:15450800, PubMed:21892188, PubMed:23102699, PubMed:23474714, PubMed:33186521, PubMed:34019811, PubMed:34321462). Mainly acts as an exo-glycohydrolase but can act as an endo- glycohydrolase at low efficiency, releasing poly(ADP-ribose) of different length as well as ADP-ribose monomers (PubMed:23102699, PubMed:23481255, PubMed:37268618). It is however unable to cleave the ester bond between the terminal ADP-ribose and ADP-ribosylated residues, leaving proteins that are mono-ADP-ribosylated (PubMed:21892188, PubMed:23474714, PubMed:33186521, PubMed:37268618). Poly(ADP-ribose) synthesized after DNA damage is only present transiently and is rapidly degraded by PARG (PubMed:23102699, PubMed:34019811). Required to prevent detrimental accumulation of poly(ADP-ribose) upon prolonged replicative stress, while it is not required for recovery from transient replicative stress (PubMed:24906880). Responsible for the prevalence of mono-ADP- ribosylated proteins in cells, thanks to its ability to degrade poly(ADP-ribose) without cleaving the terminal protein-ribose bond (PubMed:33186521). Required for retinoid acid-dependent gene transactivation, probably by removing poly(ADP-ribose) from histone demethylase KDM4D, allowing chromatin derepression at RAR-dependent gene promoters (PubMed:23102699). Involved in the synthesis of ATP in the nucleus, together with PARP1, NMNAT1 and NUDT5 (PubMed:27257257). Nuclear ATP generation is required for extensive chromatin remodeling events that are energy-consuming (PubMed:27257257). {ECO:0000269|PubMed:15450800, ECO:0000269|PubMed:21892188, ECO:0000269|PubMed:23102699, ECO:0000269|PubMed:23474714, ECO:0000269|PubMed:23481255, ECO:0000269|PubMed:24906880, ECO:0000269|PubMed:27257257, ECO:0000269|PubMed:33186521, ECO:0000269|PubMed:34019811, ECO:0000269|PubMed:34321462, ECO:0000269|PubMed:37268618}. This is the function of PARG (poly(ADP-ribose) glycohydrolase, Ensembl gene identifier ENSG00000227345).