https://morsulus.org/foswiki/bin/view/Main/WebRss
For other Foswiki webs, replace /Main/
with the name of the web:
https://morsulus.org/foswiki/bin/view/Main/WebRss
https://morsulus.org/foswiki/bin/view/Sandbox/WebRss
https://morsulus.org/foswiki/bin/view/System/WebRss