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. May be required during development to modify the walls of cells under mechanical stress. 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. Highly expressed. Predominantly expressed in stems. Expressed in shoot apical meristems, also found in seedlings and meristems. May be transcriptionally regulated by ANGUSTIFOLIA. Contains at least one intrachain disulfide bond essential for its enzymatic activity. N-glycosylated; essential for its enzymatic activity. Belongs to the glycosyl hydrolase 16 family. XTH group 2 subfamily.