The abc compiler itself is licensed under the GNU Lesser General Public License, version 2.1, or (at your option) any later version. Copyright is held by the individual contributors, a list of which can be found here. Detailed copyright information can be found from individual source files.
Soot and Polyglot are also LGPL licensed. A list of contributors to Soot can be found here and a list of contributors to Polyglot is at the bottom of this page.
The interprocedural cflow optimisations are built on Jedd, Paddle, and JavaBDD. All are licensed under the LGPL.
Our runtime library is built on the runtime library for the ajc compiler and is licensed under the Common Public License 1.0. As with the ajc runtime library, it may be freely distributed in binary form.
Our testing harness is also built in part using the ajc harness and test cases, and is similarly licensed under the Common Public License 1.0.
The harness also uses the Xact library for XML processing, which is under a BSD licence.