make-attribute

Value comes first because URI is optional argument:

CL-USER> (stp:make-attribute "123"
                             "a:defaultValue"
                             "http://relaxng.org/ns/compatibility/annotations/1.0")

#.(STP:ATTRIBUTE
   :VALUE "123"
   :LOCAL-NAME "defaultValue"
   :NAMESPACE-PREFIX "a"
   :NAMESPACE-URI "http://relaxng.org/ns/compatibility/annotations/1.0")

Without namespace:

CL-USER> (stp:make-attribute "123" "defaultValue")

#.(STP:ATTRIBUTE
   :VALUE "123"
   :LOCAL-NAME "defaultValue">