para_backing_state: RuntimeDescriptor<[_: number], {
    constraints: {
        dmp_remaining_messages: number[];
        future_validation_code?: [number, FixedSizeBinary<32>];
        hrmp_channels_out: [number, {
            bytes_remaining: number;
            messages_remaining: number;
        }][];
        hrmp_inbound: number[];
        max_code_size: number;
        max_hrmp_num_per_candidate: number;
        max_pov_size: number;
        max_ump_num_per_candidate: number;
        min_relay_parent_number: number;
        required_parent: Binary;
        ump_remaining: number;
        ump_remaining_bytes: number;
        upgrade_restriction?: UpgradeRestriction;
        validation_code_hash: FixedSizeBinary<32>;
    };
    pending_availability: {
        candidate_hash: FixedSizeBinary<32>;
        commitments: {
            head_data: Binary;
            horizontal_messages: {
                data: Binary;
                recipient: number;
            }[];
            hrmp_watermark: number;
            new_validation_code?: Binary;
            processed_downward_messages: number;
            upward_messages: Binary[];
        };
        descriptor: {
            collator: FixedSizeBinary<32>;
            erasure_root: FixedSizeBinary<32>;
            para_head: FixedSizeBinary<32>;
            para_id: number;
            persisted_validation_data_hash: FixedSizeBinary<32>;
            pov_hash: FixedSizeBinary<32>;
            relay_parent: FixedSizeBinary<32>;
            signature: FixedSizeBinary<64>;
            validation_code_hash: FixedSizeBinary<32>;
        };
        max_pov_size: number;
        relay_parent_number: number;
    }[];
} | undefined>

Returns the state of parachain backing for a given para.