NewsFox

Articles in groups can be exported to a local file in RSS 2.0 format. This can be used either for saving articles (for example from a folder of all flagged articles) or sharing with others. To share you only need to upload the file to a location accessible by others (an http site typically), and it will function as an RSS feed.

about:config

If you do not want to export categories, tags, sources or enclosures of the articles to the RSS file, you can create the preferences

newsfox.exportRSS.category
newsfox.exportRSS.tag
newsfox.exportRSS.source
newsfox.exportRSS.enclosure

and set them to false.