The Bugtraq specification defines properties for Subversion repositories to
allow client software to link commit messages to issue reports in a web-based
issue-tracking system.

See http://tortoisesvn.tigris.org/svn/tortoisesvn/trunk/doc/issuetrackers.txt
(username 'guest', no password).

Hudson could detect these properites in a Subversion working copy and use them
to find issue numbers in log messages so that appropriate hyper-links can be
inserted in the changes pages.