This directory contains file to generate source code that is part of the SwiftSyntax package. If you are looking to generate Swift code yourself, you might be interested in SwiftSyntaxBuilder.
Some source code inside SwiftSyntax is generated using SwiftSyntaxBuilder, a Swift library whose purpose is to generate Swift code using Swift itself. This kind of code generation is performed by the Swift package defined in this directory.
To re-generate the files after changing CodeGeneration run the following command on the command line.
path/to/swift-syntax/swift-syntax-dev-utils generate-source-code