The design, unless otherwise specified, is released under the CERN Open Source Hardware License version 2 permissive variant, CERN-OHL-P. A copy of the license is provided in the source repository. Additionally, user guide of the license is provided on ohwr.org. Specifically, the core design (caster.v as top level) is entirely licensed under CERN-OHL-P.
Certain target specific IP cores including DDR memory controller, asynchronous FIFO, and PLL are provided by Xilinx and licensed sepearately with use of Xilinx tools. They are not covered under the CERN-OHL-P license.
Simulation code are licensed under MIT.