E.g. https://moodle.org/mod/forum/discuss.php?d=417599#p1688163

If you download one of those linked images, and open it in a text editor, you will see that the contents of the SVG file has been replaced by

&lt;?<a href="https://moodle.org/mod/glossary/showentry.php?eid=9348&amp;displayformat=dictionary" title="Glossary of common terms: XML" class="glossary autolink concept glossaryid5">xml</a> version="1.0" encoding="UTF-8"?&gt;

So, perhaps, someone has changed the filter configuration (e.g. turned on the apply filters to files' setting without realising the consequences).

Anyway, it would be lovely if this could be fixed. It is hiding very important information. Thanks.