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.