This is the {{high-risk}} message box. It is meant to be put at the top of the documentation page on the most high-use (high-risk) templates and Lua modules (the template detects the name space), i.e., for templates used on 100,000 pages or more. For templates used on 2,000–100,000 pages, it is recommended to use the {{high-use}} template instead, which has a softer wording.

Note: It is normal that some of the links in the message box are red.

The template can be used as is. But it can also take some parameters:

{{high-risk| 300,000+ | Wikipedia talk:High-risk templates }}
{{high-risk| 300,000+ }}
{{high-risk| | Wikipedia talk:High-risk templates }}

The full code for a /doc page top may look like this:

{{documentation subpage}}
<!-- Categories go where indicated at the bottom of this page, please; interwikis go to Wikidata (see also: [[Wikipedia:Wikidata]]). -->
{{high-risk| 300,000+ }}

The /sandbox and /testcases links are the standard names for such subpages. If those pages are created then the green /doc box for the template will detect them and link to them in its heading. For instance see the top of this documentation.