jsonEncoder := json.NewEncoder(w)
			jsonEncoder.Encode(metrics)
			return
		}

		// If not JSON, return plain text. We format it as a markdown table for
		// readability.
		w.Header().Set("Content-Type", "text/plain")
		var b strings.Builder
		b.WriteString("| Name | Type | Help | Labels |\n")
		b.WriteString("| ---- | ---- | ---- | ------ |\n")
		for _, metric := range metrics {