Empty link with title attribute imediately below:
===starts ===
===stops===
<a target="_blank" href="https://www.linkedin.com/groups?gid=2178792" title="LinkedIn group"><span class="glyphicon social linkedin"></span></a>
Of course there would be a visible icon if the class was present in the CSS.
It receives tab focus, and it reads to VoiceOver and JAWS 2018. But its bad usability because the title attribute doesn't show up on keyboard focus in most browsers except IE and Edge.