json-key-type

json-key-type is a variable defined in `json.el'.
Its value is

nil

Documentation:
Type to convert JSON keys to.
Must be one of `string', `symbol', `keyword', or nil.

If nil, `json-read' will guess the type based on the value of
`json-object-type':

If `json-object-type' is: nil will be interpreted as:
`hash-table' `string'
`alist' `symbol'
`plist' `keyword'

Note that values other than `string' might behave strangely for
Sufficiently Weird keys. Consider let-binding this around your call to
`json-read' instead of `setq'ing it.