# Managing Documentation Documentation is hard. It's difficult to write, difficult to find and always out of date. That's why we implemented our in-tree documentation system that underpins firefox-source-docs.mozilla.org. The documentation lives next to the code that it documents, so it can be updated within the same commit that makes the underlying changes. This documentation is generated via the [Sphinx](http://sphinx-doc.org/) tool from sources in the tree. To build the documentation, run `mach doc`. Run `mach help doc` to see configurable options. The review group in Phabricator is `#firefox-source-docs-reviewers`. For simple documentation changes, reviews are not required. ```{toctree} :caption: Documentation :glob: true :maxdepth: 2 * ```