This template allows to differentiate between regular Template:... and Template:.../sandbox pages. It is typically used to prevent a /sandbox page being categorised with their main page.

Also

when numbered /sandbox1

Any subpage /sandboxANYTEXT is considered a /sandbox. So this includes /sandbox1, /sandbox_2.

Also

/doc

A /doc subpage is also considered a /sandbox.

This template can be used on template documentation pages to ensure that any given template sandbox or template documentation does not populate its main template's category(ies).

This template has two unnamed parameters, |1= and |2=. Near the bottom of a /doc page where the categories are usually placed, install this template as follows:

{{Documentation subpage}}
<!-- all /documentation code goes here -->
<includeonly>{{Sandbox other||
<!-- Categories the main template should be in, but not the /sandbox: -->
[[Category:(first category)]]
[[Category:(second category)]]

}}</includeonly>

• Usage of an empty first parameter (two pipes together, ||, at the end of the first line of code above) essentially means |1=(do nothing) and will not allow the sandbox page to populate the listed categories.
• Note that the closing template braces (}}) are placed just before the </includeonly> tag. This is the same as |2=(category comment and categories). In "long hand" it may appear as follows:

<includeonly>{{Sandbox other|1=<!-- keep sandbox out of categories -->|2=
<!-- Please, categories go below this line and interwikis go to Wikidata -->
[[Category:(first category)]]
[[Category:(second category)]]
(more categories if needed)

}}</includeonly>

• {{Sandbox other}} — Distinguishes between the /sandbox subpages and the root template page and other subpages.
• {{Testcases other}} — Distinguishes between the /testcases subpages and the root template page and other subpages.
• {{Template other}} — Distinguishes between pages in the template namespace and other namespaces.
• {{When on basepage}} — Distinguishes between the root template page and subpages, without special consideration in the mainspace.
• {{Subpage other}} — Distinguisheds between the root page and subpages (any subpage), classifying pagenames in the mainspace with a slash as being the root page.