With a Post made at the end of January 2018, the RSS Feed generates invalid XML
-- and, this is not the first time that this has happened -- see Bugs 1061609,
1038392, 1023370, 995015, 979651 and 976805.

The W3C Feed Validation Service <https://validator.w3.org/feed/>, provides the
following indication as to the cause of the invalid XML generation:

Sorry

This feed does not validate.

    line 1, column 1: Blank line before XML declaration [help]

            <?xml version="1.0" encoding="UTF-8"?><rss version="2.0"
         ^

In addition, interoperability with the widest range of feed readers could be
improved by implementing the following recommendations.

    line 55, column 0: content:encoded should not contain srcset attribute (4
occurrences) [help]

                        <content:encoded><![CDATA[<p><img class="alignright
wp-image-19830" src= ...

    line 55, column 0: content:encoded should not contain sizes attribute (4
occurrences) [help]

                        <content:encoded><![CDATA[<p><img class="alignright
wp-image-19830" src= ...

Source: https://news.opensuse.org/feed/

       <?xml version="1.0" encoding="UTF-8"?><rss version="2.0"
    xmlns:content="http://purl.org/rss/1.0/modules/content/"
    xmlns:wfw="http://wellformedweb.org/CommentAPI/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"