[class-prefix-selector-matching-quirks.tentative.html]
  [class="foo-bar" matches .foo-* in quirks mode]
    expected: FAIL

  [class="FOO-bar" matches .foo-* in quirks mode (the class attribute value itself is ASCII-lowercased by the quirks mode class-matching quirk)]
    expected: FAIL

  [class="FOO-bar" does not match .FOO-* in quirks mode: unlike a regular class selector, the class prefix selector itself is never case-folded, so writing it in a different case than the (quirks-mode-lowercased) class attribute never matches]
    expected: FAIL