This amplifier design is, as the American expression says, “well off the beaten path”. It does not use a global feedback loop. It is a single-ended design, operating in class-A with output voltage swing beyond its supply voltage. It has reasonable power efficiency (for an SE class-A amp, at least) while drawing a constant current from the power supply. It is a relatively simple design, has low output impedance and low harmonic distortion.
Something Different: "The Spring" SE Class-A ZGNFB MOSFET Amplifier