So
http://feed43.com/8776136547103340.xml seems to work quite well, notwithstanding that it may not be the hot-off-the-newstand version. If it is so simple I don't understand the point of leaving a totally non-functional Calibre plugin in the official list. Just modify it with this simple URL, not that the content will be a bit out of date, and move on. Leaving a broken Caliber plugin in the official list is just frustrating for thousands of users and serves no useful purpose. I believe people would prefer to have limited, out of date content to getting an inscrutable error as the current plugin now generates.