If you found this in a (like Flightsim.to, Avsim, or the .org), it’s almost certainly a custom fictional livery .
That’s a specific and interesting text string because it combines , aircraft type , and what looks like a potential typo or shorthand . livery rfs airbus a320-200
If you saw it in a , it could be an airline code you misread – e.g., RFS isn’t an ICAO or IATA code for a known passenger airline today. If you found this in a (like Flightsim