W3C HTML5 validator will issue a single warning for not having an openning html tag with the lang attribute. Other than that there are no errors. It is not brea

W3C HTML5 validator will issue a single warning for not having an openning html tag with the lang attribute. Other than that there are no errors. It is not breaking any standards. As sibling commented I would just add the html tag with the lang attribute. I don't use GTM or GA or almost any JavaScript whatsoever.