What is this?

This is my collection of plaintext versions of the Jargon File, going back to August 12, 1976.

What do the version numbers mean?

1.1.0, 1.2.0, 1.3.0 and 1.4.0 are the numbers assigned to early Jargon Files by Eric S. Raymond; 1.3.0 was identical to 1.2.0.
Previously, 1.0.3, 1.0.4, and 1.0.5 were assigned to versions I acquired that appeared to predate what ESR called 1.1.0, and so were given arbitrary preceeding numbers in apparent order of creation; 1.1.2, 1.1.3, and 1.1.5 seemed to date to the period between what ESR called 1.1.0 and 1.2.0, and so were given arbitrary preceeding numbers in apparent order of creation.
1.0.0.[1-33] numbers were systematically assigned to the versions 1-33 of AIWORD.RF as recovered from the last SAIL backup tape posted at the SAILDART Project. Arbitrary version numbers assigned to files with the same content have been deprecated, though correspondences have been marked.
2.1.1 and later have the numbers given to them by ESR.

Why zip and gzip?  Why not (bzip2|7zip|etc.)?

Zip is everywhere.  It's built into Windows XP and Mac OS X, Info-Zip's Unzip runs on a vast number of architectures, and there are other unzippers out there for things like the Apple II GS and Commodore 64.  Nothing matches zip as a universal compressed file format, whatever its deficiencies. 

Gzip is almost as common as zip, and has the useful property that clicking on a txt.gz will display the text in most modern browsers.

You're missing X!

We seem to have recovered a fairly complete archive of the earliest versions with the SAIL archive tape, but what we know we're missing are:

2.1.[2-4] -- I've never seen a citation from or pointer to these files; ESR's website mentions them, however.
2.4.2  -- Cited in older versions of FOLDOC and sources quoting those versions of FOLDOC -- Google for "Cookie Monster" to see what I mean.
2.9.[1-5,7] -- Again, I've never seen a citation from or pointer to these files; ESR's website mentions them, however.

If you have any of the above, don't hesitate to send them to jargon@jargon-file.org