This is a highly specialized product used for a specific professional video broadcasting projector. It can accept multiple 3G SDI inputs for display on a projector. SDI is still pretty much the standard used in live commercial television broadcasting. So, it has high standards for reliability, functionality, and endurance. It is HDMI without the complex cabling or copyright protection (in layman's terms).
So, while a quality product, and an expensive product, it isn't a product which has huge demand. Or almost any demand. You can throw it up on eBay at a reasonable price, and wait to see if anyone buys it or makes you an offer on it.
It won't help if you don't know what it is specifically for or have any good way to test it to show that it is functional.
I would expect the main use with the projector it is designed to be used with, is for live event projection, like in an arena, or for live video mapping.
Here are the specifications for the projector it is designed for:
https://www.projectorcentral.com/Panasonic-PT-RQ32KU.htm