For information on how to build Mozilla from the source code, see:

http://developer.mozilla.org/en/docs/Build_Documentation

To have your bug fix / feature added to Mozilla, you should create a patch and

submit it to Bugzilla (http://bugzilla.mozilla.org). Instructions are at:

http://developer.mozilla.org/en/docs/Creating_a_patch

http://developer.mozilla.org/en/docs/Getting_your_patch_in_the_tree

If you have a question about developing Mozilla, and can't find the solution

on http://developer.mozilla.org, you can try asking your question in a

mozilla.* Usenet group, or on IRC at irc.mozilla.org. [The Mozilla news groups

are accessible on Google Groups, or news.mozilla.org with a NNTP reader.]

You can download nightly development builds from the the Mozilla FTP server.

Keep in mind that nightly builds, which are used by Mozilla developers for

testing, may be buggy. Firefox nightlies, for example, can be found at:

ftp://ftp.mozilla.org/pub/firefox/nightly/latest-trunk/