I'm trying to fix a problem where the feed title is duplicated. The source of the problem appears to be in the feed related files in /wp-includes, here the line in feed-rss2.php for example:
<title><?php bloginfo_rss('name'); wp_title_rss(); ?></title>
Other posts about this problem seem to refer to plugins or themes causing the problem (Yoast SEO plugin for example). I don't have this plugin and I've also done a text search of my entire wordpress install (all folders) and the only places where either two of these names 'bloginfo_rss' and 'wp_title_rss' show up is in these feed files and where they are defined as functions (nothing is found in php files in the theme or plugin folders, only in wp-includes).
I can easily solve the problem by just removing one of these two calls in all the feed files, but I assume that will be overwritten on the next upgrade of our blog, so not only is it hackish but it also could be reverted without someone knowing about it.
Can someone explain why the feed title uses both bloginfo_rss('name') and wp_title_rss if they are always going to be the same? If they aren't really the same someone explain when they would be different and where in the dashboard I can find the editor for each of them? Settings->General is the only place I can see to edit the title.