kdeconnect-kde/plugins/mpriscontrol/propertiesInterface.xml

<?xml version="1.0"?>
<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node>
  <interface name="org.freedesktop.DBus.Properties">
    <method name="Get">
      <arg type="s" name="interface_name" direction="in"/>
      <arg type="s" name="property_name" direction="in"/>
      <arg type="v" name="value" direction="out"/>
    </method>
    <method name="GetAll">
      <arg type="s" name="interface_name" direction="in"/>
      <arg type="a{sv}" name="properties" direction="out"/>
      <annotation name="org.qtproject.QtDBus.QtTypeName.Out0" value="QVariantMap"/>
    </method>
    <method name="Set">
      <arg type="s" name="interface_name" direction="in"/>
      <arg type="s" name="property_name" direction="in"/>
      <arg type="v" name="value" direction="in"/>
    </method>
    <signal name="PropertiesChanged">
      <arg type="s" name="interface_name" direction="out"/>
      <arg type="a{sv}" name="changed_properties" direction="out"/>
      <arg type="as" name="invalidated_properties" direction="out"/>
      <annotation name="org.qtproject.QtDBus.QtTypeName.Out1" value="QVariantMap"/>
      <!-- Aparently some old version of Qt/Dbus thinks interfaces have "input" parameters --> 
      <annotation name="org.qtproject.QtDBus.QtTypeName.In1" value="QVariantMap"/>
    </signal>
  </interface>
</node>