Hello
Does anyone recognize this driver? “QY-1367” is printed on it. Can’t find anything with that model number 
It has the capability to show low battery warnings red or green (see soldering points V-, K, G, R) But I think there’s something missing, I’ve connected the LED’s but green only glows for like a second when I connect the battery… And, also I would like to boost output so a datasheet would be nice if it exists 
Thanks!
Or maybe any replacement driver that’s better? That driver has about 38mm in diameter and uses side-switch (electronic)
I should also say that the driver is for the 4 x XM-L SkyRay Kung
It looks similar to this SRK driver, but your appears to be more complex. I have the same driver as I linked, but mine has 2 FET's (One under the inductor coil). You can see the pad for it both in your and the linked pictures.
My MOSFET is the same as the one you linked:
DTU
06N03
DD13U
What does it do if there’s supposed to be two?
I wouldn't say it is supposed to be there as the driver in the above link works fine according to the OP. It's probably just another valid configuration.
I haven't tried to figure out what it's function on my driver. Last time I looked at the driver, I couldn't make out the underlying traces. Mine gets close to 7 amps of current on High (Tail measurement). Next time I have it out, I will try to take a couple pictures.