Foam on bottom of monitor motherboard
Conductive pads allow electrical connections between sub-assemblies. A foam core is covered with a conductive "fabric":

 Be very careful that the aquadag coating on the cathode-ray-tube is grounded...one or more of these pads might be used to make this ground connection to the CRT. Aquadag is the dull black/grey coating painted on much of the glass surface of the CRT. Ungrounded aquadag is electrically dangerous - high voltages are involved.