`eslint-config-env` is an ESLint configuration designed for developers creating npm packages that need to adapt to different runtime environments, such as Node.js, browsers, or frameworks like React and Next.js. It supports modern tooling like Babel, Prettier, and JSDoc, making it ideal for open-source library authors or teams building cross-platform JavaScript packages. The config automatically adjusts linting rules based on project settings like `package.json` fields, ensuring consistent code quality across environments.