A GUID used to identify the lobby software. If an application was designed to interoperate with a specific lobby using custom messages, this property can be used to identify the lobby.
However, an application should attempt to use standard messages whenever possible to be able to interoperate with as many lobbies as possible.
For this property, the dwPropertyData field of the DPLMSG_GETPROPERTYRESPONSE structure will contain the following:
GUID guidLobby;