Glycoside hydrolase that exhibits xyloglucanase activity (By similarity). Acts as an important virulence factor during P.parasitica infection of its host Nicotiana benthamiana (PubMed:28082413). Also acts as a pathogen-associated molecular pattern (PAMP) in host species, where it can trigger defense responses including cell death. The PAMP activity is independent of its xyloglucanase activity (By similarity). With paralog XLP1, is required to elevate apoplastic sugar during P.parasitica infection (PubMed:28082413). xyloglucan + H2O = xyloglucan oligosaccharides. The xyloglucanase activity is inhibited by the binding of the host apoplastic glucanase inhibitor GIP2. Interacts with host apoplastic glucanase inhibitor GIP2. Belongs to the glycosyl hydrolase 12 (cellulase H) family.