Catalyzes xyloglucan endohydrolysis (XEH) and/or endotransglycosylation (XET). Cleaves and religates xyloglucan polymers, an essential constituent of the primary cell wall, and thereby participates in cell wall construction of growing tissues (By similarity). breaks a beta-(1->4) bond in the backbone of a xyloglucan and transfers the xyloglucanyl segment on to O-4 of the non-reducing terminal glucose residue of an acceptor, which can be a xyloglucan or an oligosaccharide of xyloglucan. Predominantly expressed in green siliques. Down-regulated by auxin. Contains at least one intrachain disulfide bond essential for its enzymatic activity. Belongs to the glycosyl hydrolase 16 family. XTH group 2 subfamily.