Mozilla Firefox has transitioned its source code management from Mercurial (hg) to Git hosted on GitHub. This move marks a significant change in how the project is managed and developed, with new branch structures like 'main' and 'autoland' replacing the legacy 'mozilla-central'. While many users praise this change due to improved collaboration and consistency with widely adopted tools, some express concerns about choosing GitHub over alternatives that align more closely with open-source principles. Notably, this shift aims to facilitate tackling longstanding issues and enhance the overall efficiency of the development process.