Why it matters
Content not inside header/nav/main/footer landmarks is easy to miss when navigating by landmarks.
How to fix it
Place all visible content inside semantic landmarks.
References
More accessibility rules
void a11y reports 48 rules in this category. WCAG 2.2 AA through axe-core, plus checks axe can't do alone: visible keyboard focus, 24/44px target size on mobile, 320px reflow and disabled zoom.
html-has-lang<html> has no lang attributehtml-lang-valid<html lang> is not a valid language tagdocument-titlePage has no <title>landmark-one-mainPage has no <main> landmarklandmark-uniqueLandmarks are not uniquely identifiablepage-has-heading-onePage has no level-one headingheading-orderHeading levels skipempty-headingHeading is empty