This template inserts a Table of Contents which omits subheadings lower than a certain level. The table obeys the same layout rules as the __TOC__ magic word. Omitted sections still have section edit links in the article body; the main use for this template is situations where you want section edit links for ease of editing but don't want to clutter the table of contents.
The template defaults to including only == level 2 == and === level 3 === headers.
You can specify a different limit by adding a header level:
4 allows ==== level 4 headers ==== but omits any subheadings below that from the TOC.
The template works by hiding the lower levels with CSS. See MediaWiki:Common.css.