sej: that sounds a lot more like the NPL than the MPL. The MPL does not give any special privileges to Netscape, the only mention of Netscape in the license is that they may publish new versions of the licence, similar to GPL.
In fact, the license policy states that new original code should be licenced under MPL/GPL/LGPL tripple license. I am not quite sure why an LGPL rendering library (such as the LGPL portions of raph‘s libart) should be a problem — such a license sounds consistant with the license policy for “new non-original source files”.