Copilot for Xcode is an Xcode Source Editor Extension that provides Github Copilot and ChatGPT support for Xcode. It uses the LSP provided through Copilot.vim to generate suggestions and displays them as comments or in a separate window. The readme provides information on prerequisites, installation and setup, key bindings, permissions required, limitations, and more. It also includes a FAQ section and references to other documentation for development instruction. The app is licensed under MIT.