Per https://docs.getpelican.com/en/stable/settings.html#feed-settings:
FEED_DOMAIN = None, i.e. base URL is "/"
The domain prepended to feed URLs. Since feed URLs should always be
absolute, it is highly recommended to define this (e.g.,
“https://feeds.example.com”). If you have already explicitly defined
SITEURL (see above) and want to use the same domain for your feeds, you
can just set: FEED_DOMAIN = SITEURL.
Using `href="{{ FEED_DOMAIN }}/{{ FEED_ALL_ATOM }}"` in the template
seems to be the right way to do things, by looking at other themes, eg
the default theme in Pelican itself:
https://github.com/getpelican/pelican/blob/master/pelican/themes/simple/templates/base.html
Obviously, this change might break things for some users of the theme.
If someone used to have this definition in `publishconf.py`:
FEED_ALL_ATOM = SITEURL + '/feeds/all.atom.xml'
Then they should update to:
FEED_DOMAIN = SITEURL
FEED_ALL_ATOM = 'feeds/all.atom.xml'
Arnaud Rebillout