Code lists are organised are presented in WMO Manual on Codes I.3 https://community.wmo.int/activity-areas/wmo-codes/manual-codes
Content is in individual files, once table entry per file, in RDF TTL turtle format.
Content is published at http://codes.wmo.int/
Content is published from the Manual on Codes with best effort to deliver consistency. If doubt arises, the Manual on Codes is the authoritative source.
Pull requests are welcome from WMO expert teams.