Also, it appears ancient in this instance dates back to around 2004 or so.
It looks like a plate used to increase the threat protection of a vest. There are many such things still being made today. For example, the
Protech IMPAC.
These plates basically increases the threat protection of your vest in the area chosen. 5x7, 5x8, 7x9, etc., They add weight, thick, bulkiness, etc., but do provide more protection. My understanding is that some cops who may not have/want to carry full plate carriers can carry a plate like this that they can easily slide into place when they can anticipate needing the additional protection (serving a higher risk arrest warrant, etc.)
The one linked adds protection against higher end pistol threats, but rifle rated plates like this also exist that can be slid into a kevlar vest insert.
Hard to say what protection the one you showed provides.
Personally, I wouldn't trust them for anything (for myself or family) given their age and what little we know about the manufacturer, or even what they claim it provides. If it were me, I'd probably throw in the doomsday vault. If you ever decide to help a neighbor they can ducktape them to their chests for some makeshift armor. It's probably better than the ceramic tile options I've seen