Noticed this in the last few days, if I accelerate briskly (1/2 to 3/4 throttle) and then coast with the car in gear it will subtly backfire/pop around 2000 rpm until the clutch is pushed.

Not something I recall the car doing before, nothing has really changed with the car beyond a cleaning of the air filter element. TBH hoping this is fine because the car sounds really tough when it does it and I'd love to use it to piss off my neighbors I hate.