Apple PC Compatibility Card (Installation) - Manual (Page 9)

Removing an Apple External Video Connector
This section describes how to remove the Apple External Video Connector if
there is one installed on your computer. If your computer does not have a
video connector installed, skip ahead now to “Installing the Card.”
1 Unscrew the jack nuts from the video connector, and remove the small metal bracket.
Remove the two jack nuts and the small metal bracket.
9 Installing the PC Compatibility Card in a 5400 Series Macintosh Computer