Contributes to hydrolysis of hemicellulose, the major component of plant cell-walls. Hydrolyzes xylan to xylose and xylobiose. Endohydrolysis of (1->4)-beta-D-xylosidic linkages in xylans. Does not require any standard metal (Mg(2+), Mn2(+), Ca(2+)). Completely inhibited by Hg(2+), unaffected by EDTA. Optimum pH is 6.5, more than 80% active between pH 5.0 and 7.0. Optimum temperature is 60 degrees Celsius, more than 80% of activity remains after 1 hour at 60 degrees Celsius. Glycan degradation; xylan degradation. Belongs to the glycosyl hydrolase 10 (cellulase F) family.