The JAM chain follows a spec-first approach that lays out a formal specification for anyone to verify and implement.
Graypaper
The Graypaper is a paper with remarkable gray background written by Dr Gavin Wood to unanimously define the JAM chain. It is still subject to change until ratification by The Polkadot Fellowship.
Download it with original, dark, light background or check out the Reader.
Conformance Tests
Since the Graypaper describes everything in a mathematical way, it is difficult for implementors to verify their implementations. The Web3 Foundation provides a set of conformance tests to verify that client implementations adhere to the spec. These tests are also considered when judging the prize.
Community Resources
These resources contain personal interpretation or opinion and may not be accurate. They are still provided by the community to aid in understanding.