mark_safe not working/still escaping in simple_tag

In discussion with the author of the question we found that the characters were not actually escaped. Scoopseven (the author) viewed the source html with the option "Show Selection Source" of a context menu in Firefox. In this case escaped characters are shown.

Old thread but I ran into the same issue recently. I got it working python 3.6. Assign the value from simple tag to a variable txt and output the txt using template tags "{{" and add safe filter to txt.

{% get_contentvalue user "htmlabout" as txt %}
{{txt|safe}}