Involved in the degradation of xylan and is a key enzyme in the complete degradation of the plant cell wall. It has a specific arabinofuranose-debranching activity on xylan from gramineae. Acts synergistically with the xylanases and binds specifically to xylan. From small arabinoxylo-oligosides (ranging from arabinoxylotriose to arabinoxylohexaose), it liberates arabinose and, after prolonged incubation, the purified enzyme exhibits some xylanolytic activity as well (By similarity). Hydrolysis of terminal non-reducing alpha-L-arabinofuranoside residues in alpha-L-arabinosides. Glycan degradation; xylan degradation. Belongs to the glycosyl hydr olase 62 family.