The source code for the Adapt framework and the Adapt authoring tool is hosted on GitHub at https://github.com/adaptlearning.
The Adapt framework (FW) is a node app. Content is entered and maintained in JSON files. Technical skills are presupposed. The Adapt authoring tool (AAT) is a GUI program. A graphical user interface has been wrapped around the Adapt framework in order to make it more user friendly.
Yes, you don't buy Adapt. Adapt is open source software.