From WordPress.org
WordPress is a user-driven project, and all developments and enhancements depend on users like you! Please consider contributing to the project and the WordPress Community in one or more of the ways outlined below. Contributions from users like you keep the project vibrant, alive, and on the path of progress.
Following are the links of WordPress versions in which I have contributed to WordPress core.
If you are patinated about WordPress, then start contributing to WordPress core but before that go through with this WordPress Core Handbook. I have contributed multiple patches in below WordPress versions: