Function get_location_for_protocol_handler 

async fn get_location_for_protocol_handler(
    __arg0: AuthenticatedClientRequest<Request>,
) -> Result<ArminiusResponse<Response>, ThirdPartyError>

Handler for GET /_matrix/client/v3/thirdparty/location/{protocol} (See https://spec.matrix.org/v1.15/client-server-api/#get_matrixclientv3thirdpartylocationprotocol).

Requesting this endpoint with a valid protocol name would return the locations.

NOTE: For now, there are no supported third-parties, so it always return 404 - Not Found.