Glycoside hydrolase involved in the hydrolysis of xylan, a major plant cell wall hemicellulose made up of 1,4-beta-linked D-xylopyranose residues. Catalyzes the endohydrolysis of the main-chain 1,4-beta-glycosidic bonds connecting the xylose subunits yielding various xylooligosaccharides and xylose. Produces xylobiose and xylotriose as the main degradation products. Endohydrolysis of (1->4)-beta-D-xylosidic linkages in xylans. Glycan degradation; xylan degradation. Monomer. Not glycosylated. Belongs to the glycosyl hydrolase 10 (cellulase F) family.