XSS filtering has recently been added to swh-web (D1322) for the rendering
of README files in markdown format.

But as @kalpitk noticed it, the rendering of images located in an origin source tree
is now broken.

So instead of using [[ https://github.com/VisionistInc/showdown-xss-filter | showdown-xss-filter ]] package, prefer to use the [[ https://github.com/cure53/DOMPurify | dompurify ]]
one which seems to have a good default white list for XSS filtering.

Related T1642