I was just answering a question and saw this:
As you can see, there is no name in the third comment. What's this?
The user has used a Unicode combining character. My Firefox browser does add the link decorations to the character but I can't click on it.
A quick examination of the HTML generated for the user link shows that the character used is
U+0307 COMBINING DOT ABOVE, which combines with what appears before it. Because it is a combining mark and because the text in the
<a> link generated for the user name begins with this mark, it throws off Firefox (and maybe Chrome too) and makes the text of the user name either extremely difficult to select or maybe even impossible to select. (I sure can't select it. I had to select around it and cut and paste.)
So there is a name, just not one that is easily actionable.
It's because the owner of the comment doesn't have a name either.
From the source:
<a href="/users/790454/790454" title="1203 reputation" class="comment-user">̇̇̇</a>