It is important to point out that access to security bugs (the ones that contain descriptions of unpatched vulnerabilities) is not automatically granted to all

It is important to point out that access to security bugs (the ones that contain descriptions of unpatched vulnerabilities) is not automatically granted to all Mozilla employees, so simply having an @mozilla.com e-mail is not enough to get information on how to exploit Firefox. It is enough to get access to potentially sensitive partner information (as can be seen from the posted screenshot), but those are usually a different class of bugs from security bugs. Further, we now classify security bugs by the area of the code they affect, and give engineers access to just the areas for which they are responsible, rather than blanket access to all security bugs. This is a process that began even before the recent attacks, but we have been pushing it more aggressively in their wake.