<p dir="auto">In bootstrap.css:</p>
<pre class="notranslate">.container {
  margin-right: auto;
  margin-left: auto;
}

.container:before,
.container:after {
  display: table;
  content: " ";
}

.container:after {
  clear: both;
}

.container:before,
.container:after {
  display: table;
  content: " ";
}

.container:after {
  clear: both;
}

.row:before,
.row:after {
  display: table;
  content: " ";
}

.row:after {
  clear: both;
}

.row:before,
.row:after {
  display: table;
  content: " ";
}

.row:after {
  clear: both;
}
</pre>
<p dir="auto">Is this a bug or a feature? :)</p>
<p dir="auto">show on bootstrap.css</p>
<p dir="auto"><a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L581">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L581</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L723">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L723</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L743">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L743</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2023">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2023</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2433">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2433</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2617">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2617</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2637">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2637</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3032">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3032</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3296">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3296</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3453">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3453</a></p>