Not a lot of equestrians here (including me, Ive only ever shown a talent for falling off

However, I am obsessively curious and not hesitant to search online to find out about horse trappings, and this whatever it is does not seem to correspond to head gear. I can relate to the poor horses wearing this stuff knowing how much I 'love' my CPAP (not).
While the chains seem to resemble curb chains, the way this is closed rather than adjustable with the fixtures terminating in one loop defeats the idea of dual control , so who knows what this is. Maybe some sort of hanging loop for some sort of utility item ?