A questionmark.
<a rel="nofollow" class="external text" href="http://svn.gnome.org/viewvc/gnome-icon-theme/trunk/AUTHORS?view=markup">GNOME icon artists</a>, <a href="//commons.wikimedia.org/wiki/User:ViperSnake151" title="User:ViperSnake151">User:ViperSnake151</a> and <a href="//commons.wikimedia.org/wiki/User:Sertion" title="User:Sertion">Sertion</a>
CC BY 3.0
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Commons-emblem-issue.svg" title="File:Commons-emblem-issue.svg">Commons-emblem-issue.svg</a>: <a href="//commons.wikimedia.org/wiki/File:Commons-emblem-issue.svg" class="image"><img alt="Commons-emblem-issue.svg" src="https://upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Commons-emblem-issue.svg/24px-Commons-emblem-issue.svg.png" decoding="async" width="24" height="24" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Commons-emblem-issue.svg/36px-Commons-emblem-issue.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Commons-emblem-issue.svg/48px-Commons-emblem-issue.svg.png 2x" data-file-width="48" data-file-height="48"></a>  and <a href="//commons.wikimedia.org/wiki/File:Commons-emblem-query.svg" title="File:Commons-emblem-query.svg">Commons-emblem-query.svg</a>: <a href="//commons.wikimedia.org/wiki/File:Commons-emblem-query.svg" class="image"><img alt="Commons-emblem-query.svg" src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Commons-emblem-query.svg/24px-Commons-emblem-query.svg.png" decoding="async" width="24" height="24" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Commons-emblem-query.svg/36px-Commons-emblem-query.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Commons-emblem-query.svg/48px-Commons-emblem-query.svg.png 2x" data-file-width="48" data-file-height="48"></a>