[revert-rule-in-fallback.tentative.html]
  [var(--unknown, revert-rule) in custom property]
    expected: FAIL

  [var(--unknown, revert-rule) in shorthand]
    expected: FAIL

  [var(--unknown, revert-rule) in shorthand observed via longhand]
    expected: FAIL

  [var(--unknown, revert-rule) in longhand]
    expected: FAIL