gecko-dev/testing/web-platform/meta/domparsing/xml-serialization.xhtml.ini

[xml-serialization.xhtml]
  [DocumentType: 'QUOTATION MARK' (U+0022)]
    expected: FAIL

  [DocumentType: 'APOSTROPHE' (U+0027) and 'QUOTATION MARK' (U+0022)]
    expected: FAIL

  [ProcessingInstruction: empty data]
    expected: FAIL