On [[ https://fr.wikipedia.org/w/index.php?title=Spécial%3ARecherche | frwiki ]], the following search query (as of today) gives me one result ([[ https://fr.wikipedia.org/wiki/Utilisateur:Garfieldairlines/monobook.css | Utilisateur:Garfieldairlines/monobook.css ]]):
> [[ https://fr.wikipedia.org/w/index.php?title=Sp%C3%A9cial:Recherche&search=insource%3ADeluxeBar+intitle%3AGarfieldairlines | insource:DeluxeBar intitle:Garfieldairines ]]
(actually the "intitle" filter is only to emphasize the issue)
But if I add a [[ https://www.mediawiki.org/wiki/Help:CirrusSearch#Contentmodel | contentmodel ]] filter, the result is missing:
> [[ https://fr.wikipedia.org/w/index.php?title=Sp%C3%A9cial:Recherche&search=insource%3ADeluxeBar+intitle%3AGarfieldairlines+contentmodel%3Acss | insource:DeluxeBar intitle:Garfieldairines contentmodel:css ]]