Download
Direct access to the Subversion repository:
The live Unison sources are available for anonymous checkout using subversion, like this:

svn checkout https://webdav.seas.upenn.edu/svn/unison

You can also browse the sources by pointing any web browser at this URL:

https://webdav.seas.upenn.edu/viewvc/unison

If you get errors from svn about "Error validating server certificate", see here.