the command "bitcoin-cli getblockstats 0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba" does not work.

It displays "error: Error parsing JSON:0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba"

but it should display the block stats like the documentation says.

also bitcoin-cli getblockstats 0 does not work. block number must be at least 1 to work. But blocks start at 0.

tested with 0.20.1 on freebsd, another user on IRC acknowledged the problem.
{RPCResult::Type::STR_HEX, "hash", "The blockhash"},
                        {RPCResult::Type::NUM, "height", "Block height"},
                    }},
                RPCExamples{
                    HelpExampleCli("waitforblock", "\"0000000000079f8ef3d2c688c244eb7a4570b24c9ed7b4a8c619eb02596f8862\" 1000")
            + HelpExampleRpc("waitforblock", "\"0000000000079f8ef3d2c688c244eb7a4570b24c9ed7b4a8c619eb02596f8862\", 1000")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    int timeout = 0;
    uint256 hash(ParseHashV(request.params[0], "blockhash"));
    if (!request.params[1].isNull())
        timeout = request.params[1].getInt<int>();
    CUpdatedBlock block;
    {
        WAIT_LOCK(cs_blockchange, lock);
        if(timeout)
            cond_blockchange.wait_for(lock, std::chrono::milliseconds(timeout), [&hash]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {return latestblock.hash == hash || !IsRPCRunning();});
        else
            cond_blockchange.wait(lock, [&hash]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {return latestblock.hash == hash || !IsRPCRunning(); });
        block = latestblock;
    }
    UniValue ret(UniValue::VOBJ);
    ret.pushKV("hash", block.hash.GetHex());
    ret.pushKV("height", block.height);
    return ret;
},
    };
}
static RPCHelpMan waitforblockheight()