It provides bidirectional communication between Winamp and Girder, sending player state changes as Girder events and allowing Girder commands to in turn affect / query the state.
This file must be placed in the Plugins folder beneath where Girder is installed.
This file must be placed in the wacs folder beneath where Winamp is installed.
This file must be placed in a wacs\xml\girder folder beneath where Winamp is installed. It may be simplest to copy both girder.wac and the whole xml subfolder from the directory where the archive was unzipped into the wacs folder under Winamp3 using the Explorer.