[djsumdog]

You can protect the name and code differently. Firefox holds certain trademarks and only binaries they compile can be distributed with their branding.

You can have Firefox branding if you compile it yourself, but you can't distribute the binaries (Gentoo has a notice about this in the build process). This is why Debian created the IceWeasel package.

The museum might want to preserve the name associated with that piece of history, so Eudora always points to that final release. If the license for the code is BSD, people can of course publish their own ports with new names.