To fix this, at runtime, if the parent element of the @html element has http://www.w3.org/2000/svg namespace, it needs to add this namespace recursively.
AFAIK, as per the HTML5 specification, <svg> element and its children will automatically be the http://www.w3.org/2000/svg namespace, so if it should follow this specification, it should add this process.
However, this is a trade-off for performance but I think this processing is required for preventing user confusion.
Is there any way to avoid this now?
It is impossible to modify the namespaceURI of an already created node at runtime, and even if xmlns is written in the string entering @html, the namespaceURI is still entered incorrectly.
The only way I can think of is to give up svelte and put it in the runtime with js.