This placard was likely intended to be mounted to external velcro loop on a body armor vest like a PBPV [1]. This is similar to the panel made for tactical tailor MOLLE pouches.
Inside:
Velcro hook is attached to a panel of black 1000D cordura that is stitched onto the main chest rig body, creating a back compartment like the one found in the contemporary LBT-1961B. The compartment could also be used to store documents.
Straps:
Pouch:
Sides:
Sides have been melted to prevent fraying.