Emacs is a collaborative project and we encourage contributions from anyone and everyone.
There are many ways to contribute to Emacs:
If you would like to work on improving Emacs, please contact the maintainers at the emacs-devel mailing list. You can ask for suggested projects or suggest your own ideas.
If you have a feature request or a suggestion for how to improve Emacs, the best place to send it is to bug-gnu-emacs . Please explain as clearly as possible what change you would like to see, and why and how you think it would improve Emacs.
If you have already written an improvement, please tell us about it. If you have not yet started work, it is useful to contact emacs-devel before you start; it might be possible to suggest ways to make your extension fit in better with the rest of Emacs.
When implementing a feature, please follow the Emacs coding standards; see Coding Standards. In addition, substantial contributions require a copyright assignment to the FSF; see Copyright Assignment.
The development version of Emacs can be downloaded from the repository where it is actively maintained by a group of developers. See the Emacs project page https://savannah.gnu.org/projects/emacs/ for access details.
It is important to write your patches based on the current working version. If you start from an older version, your patch may be outdated (so that maintainers will have a hard time applying it), or changes in Emacs may have made your patch unnecessary. After you have downloaded the repository source, you should read the file INSTALL.REPO for build instructions (they differ to some extent from a normal build).
If you would like to make more extensive contributions, see the CONTRIBUTE file in the Emacs source tree for information on how to be an Emacs developer. That file is distributed as part of the source tarball of every released Emacs version, and can also be found on-line in the Emacs on-line source repository. If you cloned the Emacs repository, per the instructions in https://savannah.gnu.org/projects/emacs/, you will find this file in the top directory of the source Emacs tree.
For documentation on Emacs (to understand how to implement your desired change), refer to: