Essentialy a XML file.
Some tags are necessary in this XML file :
<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
<channel>
<title>Le Nom Des Fleurs</title>
<link>https://lndf.fr/</link>
<description>Personal Blog of Thomas Guillory</description>
<lastBuildDate>Wed, July 4 2018</lastBuildDate> <!-- optional -->then, for each item
<item>
<title>Entry Title</title>
<link>URL Link to the entry</link>
<guid>https://www.mysite.com/?p=584674</guid>
<description>This is the description of the content...</description>
<pubDate>Wed, July 4 2018</pubDate>
</item>close at the end with
</channel>
</rss>Maybe It is supposed to be named index.xml and be at
root, it seems to have helped…
<![CDATA[html here]]>