Change text “Result of filter”

In API section on the plugin’s main page I found:

BEAUTIFUL_FILTERS_INFO_POSTCOUNT
$postcount_paragraph is the default postcount string. You MUST add %d somewhere in the new string in order for the resulting number to appear.

function modify_filterinfo_postcount($postcount_paragraph){

    return 'Hej v?rlden ';

}
add_filter('beautiful_filters_info_postcount', 'modify_filterinfo_postcount');

I tried

return 'Hej v?rlden %d';

And it printed “Hej v?rlden %d” to the page, rather than “Hej v?rlden 24” or whatever number of posts were the result of filtering.

What am I missing?

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