Well, the 'driver' used a 20 MB disk image for use with the Mac286, so it's possible that the 'driver' was shipped with a 20 MB disk image. Just as how many of the questionably-legal OSx86 'Hackintosh' Torrent files aren't just for the couple-hundred-kilobyte hack-files, but are for a full disk image. Technically, that isn't *needed*, but it makes it easier to use. Likewise, I would imagine that the large file found on Torrent is the drivers PLUS the hard disk image.
Of course, after typing the above, I have determined that TB2Mac86CD.dmg is really "Timbuktu for Mac, version 8.6, CD image"