:::::It adds a banner.  It seems simple, but it's obviously not; a bot has to compensate for every way a  can possibly be formatted.  This does it with a preg_replace; it's possible to do it using other means, but they would be laborious, would use a lot more code, and would probably be a lot slower.  And  asked for an example after I requested of an editor who was going to use a bot to tag all articles in certain categories with a banner that if there were already two or more banners on the page to add the banner to  instead of leaving it floating.  —   – )  
 :::::(Sorry if all of that was incomprehensible.  It's almost 3 AM.)