g1smd - 10:04 pm on Sep 30, 2011 (gmt 0)
I'm aware that older Apache server versions (1.x and maybe some early 2.x) use only POSIX.
Which bit of
^(Moz(illa(/5\.0)?)?)$ is PCRE specific? I don't remember nesting being a problem before. Then again, I do forget a lot of stuff these days.