[about-blank-replacement.https.html]
  expected: [OK, FAIL]
  [Popup initial about:blank is controlled, exposed to clients.matchAll(), and matches final Client.]
    expected: [PASS, FAIL]

  [Nested about:srcdoc is controlled and is exposed to clients.matchAll().]
    expected:
      if fission and (processor == "x86_64") and not swgl and debug and (os == "linux"): [PASS, FAIL]
      if (processor == "x86_64") and not swgl and debug and (os == "win"): [PASS, FAIL]
      if (processor == "x86_64") and not swgl and (os == "mac"): [PASS, FAIL]