This is a git-svn clone of Indy for MY convenience. To contribute back to Indy and partcipate in the community you should definitely visit http://www.indyproject.org.
According the the Licensing page at http://www.indyproject.org/License/index.en.aspx Indy is Dual Licensed under Indy Modified BSD License and Indy Mozilla Public License.
The subversion information is at http://www.indyproject.org/sockets/download/svn.en.aspx . Note that I am doing here exactly what the Pro Git book recommends avoiding: Collaborating through both git and subversion.
Because of the particulars of our build environ and the state of our app, we needed to upgrade Indy in a way that some of our components could use the new features but that other components need not be rebuilt. We experienced considerable pain around Delphi 2010's usage of Indy and not having a clearly tagged state of the Indy code. We needed a repo we could note our own changes in.
Do not do what we are doing here.