RokGZipper is a plugin whose primary aim is to improve the performance and speed of your site. It does this by compressing your CSS (stylesheets) and JavaScript files. For javascript files, it compresses them altogether (via GZip) and places them in the cache folder. It differentiates between the pages so if you have a particular combination of scripts on one page, and a different combination on another, two files will be created and loaded independently. A similar method is used for the CSS but is based on path. To exemplify, all the CSS files in template's /css directory are combined into one file, with the module CSS files being combined elsewhere. Compressing all these files means your site can load faster.