You can download an installable HTML tarball from here.
You can download a flat-text version, with headwords and references bracketed by colons, from here. Yes, the filling/justification is badly done, with lots of rivers (makeinfo is less good at this than the Emacs Lisp code used in older versions). No, we don't care; we're trying to phase out this format.
Unfortunately, the Jargon File is far too big to email. Requests that we mail it will be ignored. Also note that the Info version has been phased out; it's an HTML world now.
In the future we hope to offer an SGML/XML version suitable for serious database work.
The masters are presently maintained in a slightly hacked variant of texinfo 3.12i, with the HTML output postprocessed by custom Perl. (This is actually a big improvement over the pre-4.1.2 setup, which involved a heavily modified version of texi2html.)
Once we are able to migrate this thing to either stock Texinfo or an SGML/XML markup, the masters and the rendering tools will be made available here. We're working with the Texinfo maintainers towards this goal.