This document provides an overview of Linux on z Systems and IBM's efforts to enable the Linux on z Systems open source ecosystem. It discusses IBM's work porting popular open source software to run on Linux on z Systems, including languages, databases, messaging, and cloud infrastructure packages. It also outlines plans to provide tools and resources to help developers access Linux on z Systems hardware and obtain ported packages. The goal is to simplify and encourage open source software development for the Linux on z Systems platform.