The source code is a key feature for your applications. If you rely on third party components, you need to access the code to perform even small customizations.
FastPdfKit ships with the sample project source code available and the full interface available with classes, xibs and storyboards.
Just the Core Rendering Engine is shipped as compiled library to prevent frauds and keep the quality hight. In the license you can find detailed informations on how the Core source code will be released if DIMENSION decides to stop supporting it.