the attribute axis contains the attributes of the context node, which are the nodes returned by the Section 5.11 parent Accessor DM31; the axis will be empty unless the context node is an element
This should reference the attributes selector (dm:attriibutes).
The axes section (https://www.w3.org/TR/xpath-31/#axes) states;
This should reference the attributes selector (
dm:attriibutes
).