Rocket Validator automatically checks your pages on the W3C Validator.
HTML issues tagged as xml.
A tag starting with
<? has been found within the document, but it’s not supported. Probable causes can be:
Copy-pasting the contents of an SVG file. If you do that, you should only paste the
<svg>...</svg>part, but not the first line with
<?...>tags on server scripting languages like PHP, like
- [freeCodeCamp: How to Use SVG Images in CSS and HTML]https://www.freecodecamp.org/news/use-svg-images-in-css-html/)
When was the last time you validated your whole site?
Keep your sites healthy checking for A11Y/HTML issues on an automated schedule.