This directory contains externs definitions for improving the precision of some of the JavaScript analyses. Externs are organized into five categories, corresponding to the subdirectories of this directory: * `es`: Externs definitions for the ECMAScript language standard; imported from the `externs` directory of the Google Closure Compiler source tree (https://github.com/google/closure-compiler). * `web`: Externs definitions for various web standards and browser-specific extensions; imported from the same source. * `vm`: Externs definitions for specific JavaScript VMs; also imported from the same source. * `nodejs`: Externs definitions for common Node.js modules; generated from the TypeScript type definitions for Node.js provided by [DefinitelyTyped](https://github.com/DefinitelyTyped/DefinitelyTyped), revision 28d94377786d6da325b76614aa4c1849dc05703e, with a few custom extensions. * `lib`: Externs definitions for popular JavaScript libraries. See the individual files for copyright and licensing information.