Ethereum Foundation announced the official release of the Ethereum Execution Layer Specification (EELS) after more than a year of development. According to the blog post, EELS is a Python reference implementation of the core components of the Ethereum execution client, focusing on readability and clarity. EELS aims to be the spiritual successor to the Yellow Paper, more friendly to programmers, and synchronized with the merged fork. EELS can fill in and execute state tests, follow the main network, and is a good framework for building new EIP prototypes.