Atom feeds output unformated raw text
The Atom feeds (at least, for issues) seem to deliver raw text. Theoretically the text in the issue description is in Markdown format as per the configuration, but if it is not rendered to HTML, the end result is a blob in the feed reader, with no paragraph breaks and with control characters mixed in.
E.g., items in https://gitlab.gnome.org/GNOME/pango/-/issues.atom appear like the attached in TT-RSS etc.
It's clear from examining the
content element in the feed source that the issue description text is in raw form.
Note that this is not how the equivalent feeds one can get via a feed-conversion tool like RSSHub or whatever work; those are able to produce content elements formatted as HTML even when the upstream source is also Markdown. E.g., following a GitHub feed via a utility like that provides readable HTML. Since the source format is known, this conversion could be done and produce readable feed content without imposing an additional burden on every reader.