# Contributing to MUI X

## MUI X vs. MUI organization

MUI X is an extension of the core open-source libraries of the MUI organization (Material UI, Base UI, MUI System).
The repositories are part of the same codebase.
`mui/mui-x` imports the code infrastructure from [`mui/material-ui`](https://github.com/mui/material-ui).
You can find the "contributing" guide for the main repository in [mui/material-ui/CONTRIBUTING.md](https://github.com/mui/material-ui/blob/HEAD/CONTRIBUTING.md).

Most of the content in the main repository "contributing" guide applies to this repository.
There are, however, a few differences:

- The default GitHub branch might be different.
- The local documentation site opens on a different port: 3001 instead of 3000.
- You would need to sign a contributor license agreement (CLA) if the PR changes code located in the following folders: `x-data-grid-pro`, `x-data-grid-premium`, `x-date-pickers-pro`
- Testing see [/test/README.md](test/README.md) for details.