This post was first published on my site , which has the full version with every figure, the wave-by-wave credits and the complete reference list.

Open edX is the open-source platform organisations around the world use to run online courses. It is not one program but more than 150 repositories, maintained by Axim Collaborative , 2U, edly Arbisoft, OpenCraft, eduNEXT and dozens of individual contributors. They share dependency constraints, reusable CI workflows, cookiecutter templates and release calendars. In 2020, the map of how they depend on each other lived only in people's heads.

Six years later there is a public dashboard at openedx.ossvitals.org that grades all 169 repositories in the Open edX GitHub organisation on nine health metrics, every day, with every weight and threshold published. I built the hosted version.…