On another site, I found a selection of four to eight different "samples" of urls that might be feeder URLs for one's site.
For regular URLs, WP Codex suggested trying out:
http://example.com/?feed=rss
http://example.com/?feed=rss2
http://example.com/?feed=rdf
http://example.com/?feed=atom
For custom permalink feeder URLs, the WP Codex suggested trying out:
http://example.com/feed/
http://example.com/feed/rss/
http://example.com/feed/rss2/
http://example.com/feed/rdf/
http://example.com/feed/atom/
I'm pretty clueless on how all this WordPress stuff works, so any help I can get...is a good thing *grin*