{
	"id": 213,
	"external_id": "user_code",
	"type": "numeric" / "numeric_discrete" / "boolean" / "choice" / "text" / "multi_boolean" / "multi_choice" / "multi_numeric" / "multi_text" / "timestamp" / "minute_of_day",
	"name": { "__": "Name", "sl": "Ime" },
	"description": "...",
	"unit": "...",

	// Only present for "choice" / "multi_choice" specs: the full list of
	// defined choices, ordered by order_weight then by id. Each entry
	// matches the choice.json shape.
	"choices": [
		{ "id": 1, "external_id": "blue", "value": { "__": "Blue" }, "order_weight": 10 },
		{ "id": 2, "external_id": "red",  "value": { "__": "Red" },  "order_weight": 20 }
	],

	// Admin-hidden flag — when true, the spec is suppressed from default
	// filter UIs and category sidebars.
	"hidden": false
}