Success! I have no indicator like the image. But I tried using the (hidden) feed icon in Firefox, and although it did not indicate any feed was available, it worked when I clicked it. After figuring-out what the actual address was I added it to my email program also. Thanks!
Gah. Anyone else having feed issues? Tried 3 apps on the Android and all failed. Tried the laptop, and Mozilla sees it, but updates are either very old or not at all. I don't know if it's entirely my end or the validation errors (link and my results below) have something to do with it? it was working great, then not so much lately.