Catalyzes the hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose in xyloglucan degradation, leading to remove the backbone 'G' units. Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose. kcat is 65.0 sec(-1) for cellotetraose. kcat is 0.62 sec(-1) for cellohexaose. Optimum pH is 6.0-7.0. Glucan metabolism; xyloglucan degradation. Periplasmic localization is predicted by analogy with the archetypal sus locus. Gut bacteria supply the human body with energy from dietary polysaccharides through glycosidases that are absent in the human genome. Xyloglucans are a ubiquitous family of highly branched plant cell wall polysaccharides present in the vegetables we consume. Enzymes involved in xyloglucan degradation mediate the conversion of otherwise indigestible plant polysaccharides to short-chain fatty acids (PubMed:24463512). Belongs to the glycosyl hydrolase 3 family.