No, it's not a Linux thing. It's a buzzer with an X.
Validation works pretty well on most websites, but some users seem to just be oblivious to errors. xBuzzer was created specifically for those users.
With a simple Javascript call, xBuzzer's patented X-buzz(TM) technology will promptly alert users to their ineptitude in a totally non-condescending manner.
<-- include this -->
<script type="text/javascript" src="//xbuzzer.org/buzzer.js"></script>
// then call this
buzz();