Also the Zigbee cluster specifications from the white-label Danfoss Ally version. As far as I can tell so far this is exactly the same product:
Sadly, I seem to be hitting a snag if I try to read a manufacturer-specific attribute (in this case, 0x4031 – “Heat Supply Request”, ref. the PDF above):
openhab> zigbee read 9040/1 0x0201 0x4031
Reading endpoint 2350/1, cluster server cluster Thermostat (0201), attributes Attribute 16433
Response for cluster 0x0201
Attribute 16433 Error UNSUPPORTED_ATTRIBUTE
This post from @chris suggests that there is a way to add those manufacturer-specific attributes to the Zigbee binding, though I’m still trying to figure out how.