Thanks! Now it works for all programs.

Thank you, that solves the issue for Inkscape. It does, however, introduce problems for all browsers. Two of them, Firefox and Chrome, at least have the courtesy to tell me what bothers them. The MS products IE and Edge just quietly fail. Firefox: “XML Parsing Error: prefix not bound to a namespace”...

On second thought, I followed Moini's tag line advice and looked at the status bar. On Ctrl-A, it does say 2 objects selected of types Circle, Clone in root. ... So it's not that Inkscape didn't read the <use> element. But why can't I see the clone? It's probably not outside of the viewBox, as I ver...

Thank you for your reply. The problem already occurs with the mozilla sample code referenced in my OP - https://developer.mozilla.org/en-US/docs/Web/SVG/Element/use. To focus on the problem I narrowed it down further to just two circles, arriving at the pair: <svg viewBox="0 0 20 10" xmlns...

How can I load a file that contains [url href=https://developer.mozilla.org/en-US/docs/Web/SVG/Element/use]use[/url] elements? Inkscape just ignores them. Sorry if this has already been asked. Searching for this tag unfortunately yields “The following words in your search query were ignored because ...