--- title: a11y/doctype · Doctype description: src/app.html should open with . --- **Severity:** info · **Category:** a11y Scored `info` rather than `warning`: the accessibility half of this rule's premise has no source. Quirks mode is documented as a layout difference, and the WCAG criterion that used to justify markup-validity checks is obsolete and removed. The layout claim stands, so the rule stands, at the weight its remaining evidence supports. ## What it checks Whether `src/app.html` opens with `` (comments before it are allowed). Project-scoped: read once from `src/app.html`. ## Why it matters Without a doctype browsers render in quirks mode, which applies different layout and box-model rules than standards mode, so a page can lay out differently from how its stylesheet was designed to behave. ## Mode differences Source analysis only: the CLI and the live dashboard's static baseline read `src/app.html`. The Vite plugin's build pass analyses prerendered HTML and never reads `src/app.html`, so it reports nothing for this rule, even though a missing doctype is visible in the output it inspects, and the dashboard's live layer does not evaluate it either; the static result stands. ## How to fix Add `` as the first line of `src/app.html`: ```html ``` ## Disabling Record the existing finding in the suppressions file (`npx svelte-vitals --update-suppressions`), or turn the rule off: ```js svelte-vitals.config.js export default { rules: { 'a11y/doctype': 'off' } }; ```