Tutorial on the configuration of a connection to a subversion repository with SQL Developer 2.1 through a proxy.
Tools > Preferences > Web Browser and Proxy
In my case, the checkout files go to the directory mywork on this location:
C:\Documents and Settings\NicolasG\Application Data\SQL Developer\mywork\Repository
SQL Developer will create a short-link to this directory in the Files view with the name mywork. See the paragraph below
These are read-only files and display the current state of your files.
MyComputer\MyWork\NameOfYourRepository\