Translations:TechDraw TemplateHowTo/31/en
3. Use the XML Editor to add a "freecad" namespace clause to the <svg>
item.
xmlns:freecad="http://www.freecadweb.org/wiki/index.php?title=Svg_Namespace"
Note that your editable texts will not work if you use "https://...", even though the wiki is reached via https these days. Since SVG is a human readable format you could also enter the line above into the file with a text editor.
Inkscape: XML Editor adding the "freecad" namespace clause to the <svg> item