papirus-icon-theme/Papirus/22x22/actions/tab-new-background.svg

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg" width="22" height="22" viewBox="0 0 22 22">
 <defs>
  <style type="text/css" id="current-color-scheme">
   .ColorScheme-Text { color:#5c616c; } .ColorScheme-Highlight { color:#5294e2; }
  </style>
 </defs>
 <path style="fill:currentColor;opacity:0.3" class="ColorScheme-Text" transform="translate(3 3)" d="M 4 2 C 4 2 2 2 2 4 L 2 11 C 2 12 1 12 1 12 L 0 12 L 0 14 L 16 14 L 16 12 L 15 12 C 15 12 14 12 14 11 L 14 4 C 14 4 14 2 12 2 L 4 2 z M 7 5 L 9 5 L 9 7 L 11 7 L 11 9 L 9 9 L 9 11 L 7 11 L 7 9 L 5 9 L 5 7 L 7 7 L 7 5 z"/>
</svg>