5/
JSON and has a 'null'. That could have been used for the 'discoverable' flag.
We could have had so that:
'discoverable' set to 'true' meant that the user explicitly chose to be discoverable.
'discoverable' set to 'false' meant that the user explicitly chose to not be discoverable.
And 'discoverable' set to 'null' meant that the user has not explicitly made a choice.