The source base of Asmeta (including the documentation and the web site) is maintained in a Subversion repository at SourceForge. The repository's URL is
You might also browse the Subversion repository online.
The file http://sourceforge.net/p/asmeta/code/HEAD/tree/readme.txt describes the organization of the repository.
Working with the Asmeta sourcesThe better way is to use eclipse and checkout the projects from the svn. You will need EMF installed.