Is there a way to view rss feeds as formatted xml that are not related to running my installation in a browser or writing my own tool?
Edit:
Preferably a method that runs on a non-Windows OS.
XML Notepad does a decent job at the right price (free).
You can also drag and drop the file into Chrome and press CTRL + U.
Code Beautify RSS Viewer is a tool for viewing RSS feeds as XML, as well as in HTML format: http://codebeautify.org/rssviewer/
Click Download, enter the URL of the RSS feed and will display the XML data on the left side and the HTML data on the right side. This tool also supports converting RSS XML to JSON.
If you view the feed in Firefox, it will read as an RSS reader, but if you view the source code, you will receive it in XML format. And you can get both on the MAC (if this is the OS you are talking about).
Just enter the feed URL in Google Chrome and it will display the results as XML