Template:Collapsible option

Use  {{Template name|state=collapsed}}  or  {{Template name|state=uncollapsed}}  to include the template so that it initially displays in, respectively, its collapsed (hidden) or uncollapsed (expanded) state.
Use  {{Template name|state=autocollapse}}  to collapse the template only if there is another template of the same type on the page.

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Editors can experiment in this template's sandbox (create | mirror) and testcases (create) pages.
Add categories to the /doc subpage. Subpages of this template.