Custom Linked Products for Magento is released under OSL-3.0 license.
Currently there are three types of product relations in Magento: Up-sells, Related Products, and Cross-sell Products. This Magento extension illustrates adding custom product relations as addition to existing Magento product relations.
Custom Linked Products for Magento source code is hosted by GitHub from where you can download current copy of its master branch:
You can also fork or contribute to Custom Linked Products for Magento by visiting its official GitHub repository page: