Theme Customizer – Text without a setting (a comment or tag)

If I understand the question right, the easiest way to implement this now is to create a new control type that doesn’t actually render any input but rather just displays your desired text. Controls have to have an associated setting, so you can register a setting with a custom type of noop so that it will not have any effect. Give the control a high priority so it will appear at the end of the section.

A more elegant solution would be to create a custom section that has this end matter as part of its template. Unfortunately, the ul is currently expected to be a direct descendent of the section container, so this is problematic.