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

(dbus-introspect-get-interface-names BUS SERVICE PATH)

Return all interface names of SERVICE in D-Bus BUS at object path PATH.
It returns a list of strings.

There will be always the default interface
"org.freedesktop.DBus.Introspectable". Another default
interface is "org.freedesktop.DBus.Properties". If present,
"interface" objects can also have "property" objects as
children, beside "method" and "signal" objects.