Support for content syndication markup languages (OPML, atom, rss, NewsML, …)

It seems to me that OPML (Outline Processor Markup Language ) was initially supported by Unfold, which no longer appears to be the case.

It would be useful if it supported a number of XML-derived formats, such as OPML (used as an exchange format in RSS readers and mind mapping software), Atom and RSS formats, as well as NewsML (developed and maintained by the IPTC), which is widely used in media and publishing for sharing structured content.

https://en.wikipedia.org/wiki/List_of_content_syndication_markup_languages