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.
return obj;
},
    };
}
namespace {
const std::vector<RPCResult> RPCHelpForDeployment{
    {RPCResult::Type::STR, "type", "one of \"buried\", \"bip9\""},
    {RPCResult::Type::NUM, "height", true, "height of the first block which the rules are or will be enforced (only for \"buried\" type, or \"bip9\" type with \"active\" status)"},
    {RPCResult::Type::BOOL, "active", "true if the rules are enforced for the mempool and the next block"},
    {RPCResult::Type::OBJ, "bip9", true, "status of bip9 softforks (only for \"bip9\" type)",
    {
        {RPCResult::Type::NUM, "bit", true, "the bit (0-28) in the block version field used to signal this softfork (only for \"started\" and \"locked_in\" status)"},
        {RPCResult::Type::NUM_TIME, "start_time", "the minimum median time past of a block at which the bit gains its meaning"},
        {RPCResult::Type::NUM_TIME, "timeout", "the median time past of a block at which the deployment is considered failed if not yet locked in"},
        {RPCResult::Type::NUM, "min_activation_height", "minimum height of blocks for which the rules may be enforced"},
        {RPCResult::Type::STR, "status", "status of deployment at specified block (one of \"defined\", \"started\", \"locked_in\", \"active\", \"failed\")"},
        {RPCResult::Type::NUM, "since", "height of the first block to which the status applies"},
        {RPCResult::Type::STR, "status_next", "status of deployment at the next block"},
        {RPCResult::Type::OBJ, "statistics", true, "numeric statistics about signalling for a softfork (only for \"started\" and \"locked_in\" status)",
        {
            {RPCResult::Type::NUM, "period", "the length in blocks of the signalling period"},
            {RPCResult::Type::NUM, "threshold", true, "the number of blocks with the version bit set required to activate the feature (only for \"started\" status)"},
            {RPCResult::Type::NUM, "elapsed", "the number of blocks elapsed since the beginning of the current period"},
            {RPCResult::Type::NUM, "count", "the number of blocks with the version bit set in the current period"},
            {RPCResult::Type::BOOL, "possible", true, "returns false if there are not enough blocks left in this period to pass activation threshold (only for \"started\" status)"},
        }},
        {RPCResult::Type::STR, "signalling", true, "indicates blocks that signalled with a # and blocks that did not with a -"},
    }},
};
UniValue DeploymentInfo(const CBlockIndex* blockindex, const ChainstateManager& chainman)