I don’t think anyone knows….Chinese manufacturer and they haven’t made much of anything available (not publicly anyway). You might read through the initial thread when rngwn discovered them a few years back (and a couple others linked). I don’t know if anyone has been able to get a data sheet or any solid info about binning/groups. If Simon was able to, it might be buried in his main thread here.

WTS/GB: [4000k ARRIVED, Test Report's In] GT-FC40 (a.k.a. XHP70's flattop, 12v 40w sister) 95 CRI, Available in 4000k, 5000k (Maukka and djozz tests linked)

Generally above BBL. I haven’t seen beamshots that look “nice” at lower outputs but it’s not bad with more juice.

Mfr page for the family although they still have not updated it to show the FC40: 30W COB LED, flip chip led, led with copper base