This repository contains the TC39 proposal for adding enum declarations to ECMAScript. The proposal aims to introduce a syntax and semantics for enums that are compatible with TypeScript's enums, with some differences such as the removal of auto-initializers and reverse mapping. The repository includes the specification written in Ecmarkup, a grammar file extending the ECMAScript grammar, and a build system to generate the HTML specification. The architecture is centered around generating the specification document. The source files (in src/) are processed by gulp and ecmarkup to produce the final HTML specification in the docs/ directory. The build system uses standard gulp tasks for cleaning, building, watching, and serving the documentation. While the specification itself is well-crafted and follows the Ecmarkup conventions, the build system relies on outdated versions of gulp and related plugins, indicating some technical drift. The repository does not contain any broadly reusable software components outside of the context of generating this specific specification.