x1 is the ICAO (International Civil Aviation Organization; French: Organisation de l'aviation civile internationale, OACI) designation/result/standard/code for general subject type x2 (contextless default probably: airports) applied to specific case/entity/procedure/group/hub/terminus/location x3 according to rule/ICAO specification/publication x4 published by/according to mandating organization x5 (default: ICAO)