It is built into the case of the M 380, but differs from that mic in just about every other respect. The TG-X 50 is hypercardioid, and uses a traditional moving-coil capsule rather than a repurposed headphone driver.
The TG-X 50 capsule was taken from the TG-X 80 handheld vocal microphone. The same capsule shows up in the Opus 99, M 99 TG, and Opus 65.
The mic had no output transformer or other circuitry of any kind. The schematic shows a hum-compensation coil, but this is built into the capsule itself.