The Ethereum Execution Client Specifications repository serves as a comprehensive source for the technical guidelines of the Ethereum execution client, focusing on the pyspec and network upgrade specifications. It encompasses extensive documentation of Ethereum Protocol Releases, detailing each version’s block number, release date, and the Ethereum Improvement Proposals (EIPs) integrated within each iteration, from Frontier to Shanghai and beyond. The repository highlights the transition to timestamp-based upgrade activations post-Paris. The ongoing Python-based execution specification prioritizes clarity and simplicity, complemented by detailed narrative and API documentation. It is maintained as a Python library compatible with Python 3.10+, facilitating integration with testing tools, and can be built using tox for documentation rendering. The specifications are open-source under the Creative Commons Zero v1.0 Universal license, underscoring their accessibility and collaborative development ethos.