The .tgz files extract into a folder identical to their names, as is the common convention for .tgz files. The .zip files extract into the current directory, as is the common convention for .zip files. (I hate not knowing what to expect, which is why I'm saying.) The folders contain all of the files for each release, just in case you only want to look at what's in there without downloading the whole package. I don't know about you, but I end up deleting most things I download, so it'd save me a lot of time if other people would do what I've done here. The "unreleased" folder contains a copy of my personal version of Sarcasm, which is usually always under development, and is automatically copied from my computer each time I update my web site. It should almost always contain a working version of Sarcasm, but the feature set may change in ways that won't be fully documented until it is assigned a version number. You can examine its change log to see the differences between it and the latest release.