{ "$schema": "http://json-schema.org/draft-04/schema#", "type": "object", "allOf": [{ "$ref": "core#/definitions/state_event" }], "properties": { "content": { "type": "object", "properties": { "topic": { "type": "string" } }, "required": ["topic"] }, "state_key": { "type": "string", "pattern": "^$" }, "type": { "type": "string", "enum": ["m.room.topic"] } } }