The document discusses a data layer in Clojure, focusing on the Onyx framework, which enables near real-time data processing and supports both batch and streaming machine learning workflows. It highlights the functionality, architecture, and self-service infrastructure for data scientists, as well as the use of Clojure for data manipulation and the automatic generation of materialized views based on event data. Finally, it emphasizes the importance of clean architecture and the concept of 'data is code' in structuring data processing.