I downloaded the source code in an attempt to learn how the whole Flowable stack works. Of course, with so many moving parts, I am facing some issues as to where to start. I’m guessing a good point would be the core engine. Is it located at https://github.com/flowable/flowable-engine/tree/master/modules/flowable-engine/src/main/java/org/flowable/engine? If so, which implementation files might form the cornerstone of the engine?