https://tracker.moodle.org/browse/MDL-24895 introduced the class no-overflow for format_text in many areas of moodle.

While this was useful in non-responsive themes, it is not so useful for most moodle themes in 2017.

The additional div adds scrollbars and padding to content.

I believe this was implemented to show content which is larger than the container the content is displayed in.
 
.no-overflow {
overflow: auto; padding-bottom: 1px;
}
 
Currently this causes scrollbars to be displayed on lots of content where they are not needed, which unfortunately makes Moodle look rather dated and ugly.
 
There are areas of Moodle which do benefit from no-overflow scrollbars (e.g. large tables, scorm etc).
 
But for the majority of places where format_text is applied such as a topic summary, resource/activity titles, resource/activity description and the many other areas which use format_text we no longer require this wrapper div and the associated scrollbars and padding.
 
Please feel free to ask any questions in the associated thread on the moodle theme forum : https://moodle.org/mod/forum/discuss.php?d=349061