What is the difference between Copilot and GitHub Copilot X?

GitHub Copilot X was the branding used during the preview phase of features like Copilot Chat, voice coding, and pull request summaries. These features have since been integrated into GitHub Copilot under the standard plans. If you see references to "Copilot X" in older content, those features are now just part of regular Copilot — the "X" branding has been retired.