NetworkManager/introspection/nm-device.xml

<?xml version="1.0" encoding="UTF-8" ?>

<node name="/">
  <interface name="org.freedesktop.NetworkManager.Device">
    <method name="Deactivate">
      <annotation name="org.freedesktop.DBus.GLib.CSymbol" value="impl_device_deactivate"/>
    </method>

    <property name="Udi" type="s" access="read"/>
    <property name="Interface" type="s" access="read"/>
    <property name="Driver" type="s" access="read"/>
    <property name="Capabilities" type="u" access="read"/>
    <property name="Ip4Address" type="i" access="read"/>
    <property name="State" type="u" access="read"/>
    <property name="Ip4Config" type="o" access="read"/>
    <property name="Carrier" type="b" access="read"/>

    <!-- Ugh, but I see no other way of getting the type on the caller
         based on dbus object path only -->
    <property name="DeviceType" type="u" access="read"/>

    <signal name="StateChanged">
      <arg name="state" type="u"/>
    </signal>

    <signal name="CarrierChanged">
      <arg name="carrier_on" type="b"/>
    </signal>

  </interface>
</node>