About [[MediaWiki:Tux-message-filter-result/en]]

I don't understand the case "not a query string but some sort of text" you're talking about, could you please add a screenshot?

There is no way to explicate that with a screen shot.

The search field has a background string which is shown when nothing has been entered. This string is replaced as $2 in Tux-message-filter-result ("Found $1 {{PLURAL:$1|result|results}} for "$2"") but is arbitrary text, not a search string.

I suggest to avoid to pass anything else but the true search string as $2 to Tux-message-filter-result ("Found $1 {{PLURAL:$1|result|results}} for "$2"")

Thanks for clarifying. As I suspected, this is bugzilla:47039 again, not a l10n problem