Apache Subversion (also called subversion repository and SVN) is an internetsoftware mainly used by softwareprogrammers. Subversion allows other developers to view the code easily.
To download files in a directory of a subversion repository, one can "checkout" using a subversion client.
Further reading
C. Michael Pilato, Ben Collins-Sussman, Brian W. Fitzpatrick; Version Control with Subversion; O'Reilly; ISBN0-596-00448-6 (1st edition, paperback, 2004, full book online, mirror)
Mike Mason; Pragmatic Version Control Using Subversion; Pragmatic Bookshelf; ISBN0-9745140-6-3 (1st edition, paperback, 2005)
William Nagel; Subversion Version Control: Using the Subversion Version Control System in Development Projects; Prentice Hall; ISBN0-13-185518-2 (1st edition, paperback, 2005)