This document discusses PyroCMS, an open-source content management system built with CodeIgniter. It provides background on PyroCMS, including that it originated from StyleCMS and was rebuilt after StyleDNA failed. It outlines basic principles for PyroCMS such as making the CMS intuitive for clients but difficult for them to break, and using a logical folder structure. It also discusses managing the PyroCMS codebase through master, branches, tags and forks on GitHub.