cbid(section_id) {
		if (section_id == null)
			L.error('TypeError', 'Section ID required');

		return 'cbid.%s.%s.%s'.format(
			this.uciconfig ?? this.section.uciconfig ?? this.map.config,
			section_id, this.option);
	}
Obtain the internal ID ("cbid") of the element instance.

Since each form section element may map multiple underlying
configuration sections, the configuration section ID is required to
form a fully qualified ID pointing to the specific element instance
within the given specific section.

@param {string} section_id
The configuration section ID

@throws {TypeError}
Throws a `TypeError` exception when no `section_id` was specified.

@returns {string}
Returns the element ID.