Welcome aboard! No useful hits on a google search for “gml100-pfc” so I guess your best bet is to power the LED driver and measure what is coming in and out of the pins of the inductor (voltage and current) to try and identify the part. One of the meanings of PFC is power factor correction, and I think LED lights running from the power line need power factor correction, but I don’t know much more than that about it. If your driver is intended to run from the power line that may be what this is or it may not be . It could be simply a transformer that translates the power line to the low voltage / higher current needed by LEDs. Measuring a working unit is likely your best bet to figure it out.