- it runs all the JavaScript files through jsure (similar to jslint but more configurable) to look for possible parse errors in the code

- it builds jo.js, which is the library baked into a single file

- if you have jsmin, it also makes jo_min.js which is the same thing but with no comments and extra spaces (smaller JS file). jsmin is not a strong compressor, but it is safe and readily available. Any JS compressor will work, and the Makefile will be a bit more flexible in the future to let you configure your preferred compression util.

- make also builds a local copy of the documentation (found in docs/html) from the source code and any *.mdown files in the directory tree.

Now, that's all developer stuff. If you just want to use Jo, you only need jo_min.js. Also, unless you're ready to make your own CSS, you should grab the files in css/aluminum.

Hope that helps!