Module:Is infobox in lead checks if a given infobox is in the lead, is also the only infobox in the lead, and that there aren't two of that same infobox in the article. If that is the case, it returns true, and if not returns nothing.
This is designed for use by infoboxes that automatically generate short descriptions, to make sure they only generate a short description if they are the lead infobox.
<nowiki>{{#invoke:Is infobox in lead|main|[Ii]nfobox [Ff]oo [Bb]ar}}</nowiki>
It does not detect redirects which do not match the parameter. Redirects can be handled with an extra invocation per redirect pattern, e.g.:
<nowiki>{{#invoke:Is infobox in lead|main|[Ii]nfobox [Ss]ong}}{{#invoke:Is infobox in lead|main|[Ii]nfobox [Ss]ingle}}</nowiki>
Redirects can be found with [{{fullurl:Special:WhatLinksHere|hidetrans=1&hidelinks=1&target=Template%3AInfobox+(enter+real+name+of+infobox+here)}} WhatLinksHere].