dbus-introspect-get-property is a compiled Lisp function in `dbus.el'.

(dbus-introspect-get-property BUS SERVICE PATH INTERFACE PROPERTY)

This function returns PROPERTY of INTERFACE as XML object.
It must be located at SERVICE in D-Bus BUS at object path PATH.
PROPERTY must be a string, element of the list returned by
`dbus-introspect-get-property-names'. The resulting PROPERTY
object can contain "annotation" children.