A backport is a piece of software which has been backported - to which a fix has been retroactively applied to a previous version of a piece of software.
OS X was forked from the FreeBSD 2.x/3.x branch. with kernel mods and the quartz userland. the various OS X releases have corresponding FreeBSD releases. it uses the FreeBSD mach microkernel with os9 compatibility. Darwin is the development builds of OS X versions. the FreeBSD guys backport OS X tech into their OS. OS X is opensource aside from the quartz userland. OS X also includes kernel components from the NeXT step operating system.
Ubuntu will not make an official Firefox 3.5 package for Intrepid (8.10) since it is not considered a critical security fix, and support for Intrepid will be retired before Firefox 3.0 reaches end-of-life. Because Intrepid is near end-of-life, there's also been little interest in making a backport package.You have a few options:1. Upgrade to Jaunty (9.04). There is a package of Firefox 3.5 already in the repos.2. Use the Mozilla team's PPA of Firefox 3.5 builds. These are development builds, and may not be completely stable. Add the following to your /etc/apt/sources.list filedeb http://ppa.launchpad.net/ubuntu-mozilla-daily/ppa/ubuntu intrepid maindeb-src http://ppa.launchpad.net/ubuntu-mozilla-daily/ppa/ubuntu intrepid main Then 'sudo apt-get update' and 'sudo apt-get install firefox-3.5'3. Compile the source yourself.4. Use Firefox's precompiled binary tarball.