Plan identifier tag.
{ "$schema": "https://json-schema.org/draft/2020-12/schema", "$id": "#/components/schemas/bill-subs-api_rate-plan_components-schemas-identifier", "title": "bill-subs-api_rate-plan_components-schemas-identifier", "description": "Plan identifier tag.", "example": "free", "readOnly": true, "type": "string" }