Optional$schema?: stringThe URL of the JSON Schema of the format version of the file, MAPJSON_SCHEMA_URL, e.g. for
editors that check a file while it is written. The editor writes it; a reader does not need it.
Optionalversion?: numberThe version of the format of the file: 1. A file without it is of version 1.
The content of a .mapjson file: a map state with the URL of its schema.