ਫਰਮਾ:Not a sandbox

Returns "/sandbox" if the template detects that the page where it is transcluded is a subpage named "sandbox" (i.e. a sandbox page); otherwise it returns nothing.

This can be useful to e.g. switch the version of a template used in its /doc[umentation] to the version in its sandbox (by replacing ਫਰਮਾ:((template_name ... on the /doc page with ਫਰਮਾ:((template_name{{\sandbox}} ...) when that documentation is transcluded on the template's sandbox page.