Brandon Moeller

This plugin allows publishers to better control the width of photos that use the WordPress caption shortcode feature, when that content is displayed in RSS feed readers like Google Reader, as displayed on small-screen mobile devices.
This plugin accomplishes the same thing that adjusting the “function img_caption_shortcode” code in includes/media.php would, but allows the user to automatically update WordPress without worrying about losing these changes.
It is the author’s hope that in future releases of WordPress (post 3.3), this plugin will prove unnecessary if (hard-working, responsive-minded) WordPress core developers decide to include the fix in newer versions of the awesome great open source software we have all come to love.
The code for this plugin was inspired by code found on this page of the codex: 
<a href="https://codex.wordpress.org/Function_Reference/add_filter" rel="nofollow ugc">https://codex.wordpress.org/Function_Reference/add_filter</a>
Read more about RSS Responsive Caption on the author’s website here: 
<a href="http://brandonmoeller.com/blog/2011/12/18/rss-responsive-caption/" rel="nofollow ugc">http://brandonmoeller.com/blog/2011/12/18/rss-responsive-caption/</a>

RSS Responsive Caption

Improves WordPress caption elements so captioned images in RSS feeds responsively adjust to fit within Google Reader’s screen on Android devices.

P. Chandra

Adds copyright notice at end of articles in full text RSS feeds, with back links to the blog and original article.
A notice gets attached at the bottom of feed articles like this 
Original Article: Title of Article (linked to permalink) 
Copyright Year. Blog Title (linked). All Rights Reserved
Your Blog title is linked to your blog Url. Your article title is linked to the article permalink.
Blog copyright notices are important as your feed gets freely distributed across the web and is republished without permission by RSS scrappers and autoblogs. After using this plugin, now RSS scrappers will link back to your site, which will suggest to search engines that your blog and article was the original source.

Simple Feed Copyright

Adds copyright notice at end of articles in full text RSS feeds, with back links to the blog and original article.

RSS Responsive Caption vs Simple Feed Copyright