The source code for Prolint is managed in a Subversion repository, here at the OpenEdge Hive.
You can also find a Subversion repository at Sourceforge.net, but that one is outdated.
View the repository in your web browser:
http://websvn.oehive.org/listing.php?repname=prolint
or if you prefer to use a subversion client (like svn.exe or TortoiseSvn) then you can export the trunk from svn://oehive.org/prolint/trunk/prolint