.htmlhintrc

{
    "$schema": "https://www.schemastore.org/htmlhint.json",
    "alt-require": true,
    "attr-lowercase": true,
    "attr-no-duplication": true,
    "attr-no-unnecessary-whitespace": true,
    "attr-sorted": false,
    "attr-unsafe-chars": true,
    "attr-value-double-quotes": true,
    "attr-value-no-duplication": true,
    "attr-value-not-empty": false,
    "attr-value-single-quotes": false,
    "attr-whitespace": false,
    "button-type-require": true,
    "doctype-first": true,
    "doctype-html5": true,
    "frame-title-require": true,
    "h1-require": false,
    "head-script-disabled": false,
    "href-abs-or-rel": false,
    "html-lang-require": true,
    "id-class-ad-disabled": true,
    "id-class-value": false,
    "id-unique": true,
    "inline-script-disabled": true,
    "inline-style-disabled": false,
    "input-requires-label": true,
    "main-require": false,
    "meta-charset-require": true,
    "meta-description-require": false,
    "meta-viewport-require": false,
    "space-tab-mixed-disabled": "space",
    "spec-char-escape": true,
    "src-not-empty": true,
    "style-disabled": false,
    "tag-no-obsolete": true,
    "tag-pair": true,
    "tag-self-close": false,
    "tagname-lowercase": true,
    "tagname-specialchars": true,
    "tags-check": true,
    "title-require": true
}