Importing package files from version control repositories based on CVS and SubVersion is something supported by the JSClasses since some time earlier this year.
Now importing packages files from Git repositories is also supported in the JSClasses.
The way it works is the same as in the PHPClasses site. Read this article that gives you more details on how to import package files from Git, SubVersion and CVS. Also watch the tutorial video in the article to see how to do it in practice.
