ric) limit of sigops in blocks
  "sizelimit" : n,                         (numeric) limit of block size
  "weightlimit" : n,                       (numeric, optional) limit of block weight
  "curtime" : xxx,                         (numeric) current timestamp in UNIX epoch time
  "bits" : "str",                          (string) compressed target of next block
  "height" : n,                            (numeric) The height of the next block
  "signet_challenge" : "hex",              (string, optional) Only 