chromium/chrome/browser/resources/tab_strip/alert_indicators/picture_in_picture_alt.svg

<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16"><path d="M16 14H0V2h16v12zM1 13h14V3H1v10zm7-5h6v4H8z"/></svg>