These archives contain older versions of Yags, going back to 1998 or so. The core mechanics changed quite a bit before version 0.4. Version 0.4 saw things settle down to more or less how they are now, at least as far as the core mechanics are concerned.
Unlike newer versions of Yags, these versions are released under a BSD-style license.
Version 0.2 was the first to use multiplication for attributes and skills, though it kept skills as a percentage, so attributes were multiplied by a fraction.
Version 0.3 (Babylon 5)
The main thrust of version 0.3 was for a Babylon 5 campaign I started running. This is currently the only Science Fiction version of Yags.
The main changes was reducing the average attribute from 20 to 12, and splitting the rules into seperate articles.
Some non-Babylon 5 related rules are also available for this version of the rules.