id
This attribute defines the current URI of this schema (this attribute is effectively a "self" link).
This URI may be relative or absolute. If the URI is relative, it is resolved against the current URI of the parent schema it is contained in.
If this schema is not contained in any parent schema, the current URI of the parent schema is held to be the URI under which this schema was addressed.
If id is missing, the current URI of a schema is defined to be that of the parent schema. The current URI of the schema is also used to construct relative references such as for $ref.