File bugs. Chromium and Firefox are not black boxes.
A few examples that come to mind:
https://code.google.com/p/chromium/issues/detail?id=67587
https://code.google.com/p/chromium/issues/detail?id=178297
https://bugs.webkit.org/show_bug.cgi?id=102914
File bugs. Chromium and Firefox are not black boxes.