Hydrolyzes 1,4-beta linked polysaccharide backbones of xylans, one of the major hemicellulose components in hardwoods and softwoods. It is more active against xylopentaose than xylotetraose, has trace activity against xylotriose. The major products released from hydrolysis of xylooligosaccharides are xylobiose and xylotriose. The reiterated 40 AA domain is involved in binding the cellulase-hemicellulase complex. Endohydrolysis of (1->4)-beta-D-xylosidic linkages in xylans. Glycan degradation; xylan degradation. Consists of an N- and C-terminal catalytic domains linked to a middle reiterated domain. Only the C-terminal catalytic domain is active. Belongs to the glycosyl hydrolase 11 (cellulase G) family.