1. you have to select: do you want that your posts can be used by someone else to get the XML icon (so have a hyperlink to the RSS feed).
bug / security issue:
Even when you do not select this option you can have the RSS feed by adding the ?view=rss at the end of the blog-URL. That’s bad.
The explanation of BNN by explaining the XML icon:
With XML someone can use your message at his/her own site. XML is just a kind of code. And that’s it.
