Versioning and Specs

[joto]

Any kind of change to the API, data model, etc. means we need to think about versioning. Part of that discussion needs to be what we are versioning, the API? the data model? (what is part of that data model)? File formats? And we'd need some "official" specification probably, at least something more than a wiki page that everybody can change (or the always popular: the code is the specification).

Some discussion is here: openstreetmap/openstreetmap-website#2353