The main article title is hidden when printing from the mobile Wikipedia. This is due to print-specific CSS which hides the entire .header element, which contains the title of the article.
Developer notes
Instead of hiding .pre-content I suggest hiding .minervatab-container, .page-actions-menu, minervasubtitle
Explicit seems better here and I assume we want to show tag line if shown (wikidata description) as well as title.