Endo-acting xylanase which displays no detectable activity against polysaccharides other than xylan. Hydrolyzes glucosidic bonds with retention of anomeric configuration. Endohydrolysis of (1->4)-beta-D-xylosidic linkages in xylans. Glycan degradation; xylan degradation. Belongs to the glycosyl hydrolase 11 (cellulase G) family.