babel.config.js- Babel project-wide configuration.
.babelrc,.babelrc.js- Babel file-relative configuration.Babel is a compiler for next generation JavaScript.
.browserslistrc- Browserslist config.Browserslist is the config to share target browsers and Node.js versions between different front-end tools.
composer.json- Composer project setup.Composer is a dependency manager for PHP.
_config.yml,_config.toml- Jekyll configuration.Jekyll is a blog-aware static site generator in Ruby.
.dockerignore- To exclude files and directories in Docker build.Docker is an engine to package any application and all its dependencies in a container that can run on any infrastructure.
.editorconfig- Defining coding styles across various editors and IDEs.EditorConfig helps maintain consistent coding styles for multiple developers working on the same project across various editors and IDEs.
.eslintignore- To ignore specific files and directories from linting by ESLint.-
.eslintrc,.eslintrc.js,.eslintrc.json,.eslintrc.yml,.eslintrc.yaml- ESLint configuration file.ESLint is a static code analysis tool for identifying problematic patterns found in JavaScript code.
gatsby-config.js- Site configuration options for a Gatsby site.Gatsby is a static site generator based on React.
.gitattributes- Git settings for a project.-
.gitignore- To specify intentionally untracked files that Git should ignore.Git is a distributed version control system for tracking changes in source code.
.gitlab-ci.yml- GitLab CI/CD pipelines configuration.GitLab is a Git-repository hosting service.
Gemfile- A format for describing gem dependencies for Ruby programs.RubyGems is a package manager for the Ruby programming language.
.huskyrc,.huskyrc.json,.huskyrc.yaml,huskyrc.yml,.huskyrc.js,husky.config.js- Husky configuration.Husky is a tool that makes Git hooks easy.
jest.config.js- Jest configuration.Jest is a JavaScript testing framework.
jsconfig.json- A file to specify the options for the features provided by the JavaScript language service.
lerna.json- Lerna configuration file.gLerna is a tool for managing JavaScript projects with multiple packages.
.lintstagedrc,lint-staged.config.js- lint-staged configuration.lint-staged runs linters against staged git files.
.markdownlint.json- markdownlint config file.markdownlint is a Node.js style checker and lint tool for Markdown/CommonMark files.
netlify.toml- Netlify file-based configuration.Netlify is a platform that offers hosting and serverless backend services for web applications and static websites.
next.config.js- Next.js configuration file.Next.js is a React framework which gives you the best developer experience with all the features you need for production: hybrid static & server rendering, TypeScript support, smart bundling, route pre-fetching, and more.
.node-version- Node version configuration for nodenv.nodenv is a version manager for Node.js.
.npmrc- npm config file.npm (originally short for Node Package Manager) is a package manager for the JavaScript programming language.
nuxt.config.js- Nuxt.js configuration.Nuxt.js is a progressive framework based on Vue.js to create modern web applications.
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.nvmrc- nvm (Node Version Manager) configuration.nvm is a version manager for node.js, designed to be installed per-user, and invoked per-shell.
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package.json- A file that lists package dependencies and includes other metadata for npm package. 
postcss.config.js- PostCSS configuration.PostCSS is a tool for transforming CSS with JavaScript.
.prettierignore- To exclude files from formatting by Prettier.-
.prettierrc,.prettierrc.js,.prettierrc.json,.prettierrc.yml,.prettierrc.yaml,.prettierrc.toml,prettier.config.js- Prettier configuration file.Prettier is an opinionated code formatter.
pubspec.yaml- A file that lists package dependencies and includes other metadata, such as a version number for pub packages.pub is a package manager for the Dart programming language.
renovate.json- Renovate configuration file.Renovate keeps source code dependencies up-to-date with multi-platform and multi-language using automated Pull Requests.
.ruby-version- Ruby version configuration for rbenv or RVM.rbenv and RVM are Ruby environment (version) managers.
.stylelintrc,.stylelintrc.js,.stylelintrc.json,.stylelintrc.yml,.stylelintrc.yaml,stylelintrc.config.js- stylelint configuration.stylelint is a mighty, modern linter that helps you avoid errors and enforce conventions in your styles.
tailwind.config.js- Tailwind CSS configuration.Tailwind CSS is a utility-first CSS framework for rapidly building custom designs.
.travis.yml- Travis CI build configuration and settings.Travis CI is a hosted continuous integration and deployment system.
tsconfig.json- TypeScript configuration.TypeScript is a strict syntactical superset of JavaScript and adds optional static typing to the language.
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tslint.json- TSLint configuration.⚠️ TSLint has been deprecated as of 2019. TSLint is an extensible static analysis tool that checks TypeScript code for readability, maintainability, and functionality errors. 
vue.config.js- Vue CLI config file.Vue.js is a model–view–viewmodel JavaScript framework for building user interfaces and single-page applications.
.watchmanconfig- Watchman configuration file.Watchman exists to watch files and record when they change. It can also trigger actions (such as rebuilding assets) when matching files change.
webpack.config.js- webpack configuration file.webpack is a module bundler. Its main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.
wp-cli.local.yml,wp-cli.yml- WP-CLI config files.WP-CLI is the official command line tool for interacting with and managing your WordPress sites.
.wp-env.json- wp-env configuration.wp-env lets you easily set up a local WordPress environment for building and testing plugins and themes.
.yarnrc- Allows you to configure additional Yarn features.Yarn is an alternative to npm for installing modular JavaScript.