MDA - markup/xml/xpath/xpath-location-step

Comment:: node test: simply something which matches (or not a particular node)
Comment:: some shortcuts: child:: is default axis -- attribute::aaa can be abbreviated as @aaa -- // is /descendent-or-self::node() -- . is self::node() -- .. is parent::node()
Comment:: steps consist of: direction, node test, optional predicates
Comment:: direction: defined by the axis -- child:: down to children -- parent:: to parent, sideways to siblings, ....
Comment:: optional predicates: boolean tests in the context of the node currently considered -- if all tests pass, current node is part of the result

References: