Sorry for the delay in getting back to you. Your question sparked a bug hunt which we wanted to fix first.
We’re going to discourage people from using the metadata tags as, as you’ve discovered, they’re not well documented and will likely be deprecated from Dashboard in the future.
Littlefoot arrays are not yet supported in the current Dashboard or Blocks Code releases. You can expect them in the next release, but I can’t give an estimate for when that might be.