anchor.diff:    :marked
       See "[Why peerDependencies?](#why-peer-dependencies)" below for background on this requirement.
   :marked
  -  ***core-js*** - monkey patches the global context (window) with essential features of ES2015 (ES6).
  +  ***core-js*** - Monkey patches the global context (window) with essential features of ES2015 (ES6).
      Developers may substitute an alternative polyfill that provides the same core APIs. 
      This dependency should go away once these APIs are implemented by all supported ever-green browsers.
     
  -  ***reflect-metadata*** - a dependency shared between Angular and the ***TypeScript compiler***. 
  +  ***reflect-metadata*** - A dependency shared between Angular and the ***TypeScript compiler***. 
     Developers should be able to update a TypeScript package without upgrading Angular, 
     which is why this is a dependency of the application and not a dependency of Angular.
     
  -  ***rxjs*** - a polyfill for the [Observables specification](https://github.com/zenparsing/es-observable) currently before the 
  +  ***rxjs*** - A polyfill for the [Observables specification](https://github.com/zenparsing/es-observable) currently before the 
     [TC39](http://www.ecma-international.org/memento/TC39.htm) committee that determines standards for the JavaScript language.
     Developers should be able to pick a preferred version of *rxjs* (within a compatible version range) 
     without waiting for Angular updates.
     
  -  ***zone.js*** - a polyfill for the [Zone specification](https://gist.github.com/mhevery/63fdcdf7c65886051d55) currently before the 
  +  ***zone.js*** - A polyfill for the [Zone specification](https://gist.github.com/mhevery/63fdcdf7c65886051d55) currently before the 
     [TC39](http://www.ecma-international.org/memento/TC39.htm) committee that determines standards for the JavaScript language.
     Developers should be able to pick a preferred version of *zone.js* to use (within a compatible version range) 
     without waiting for Angular updates.
  
positive.code:   Good for demos, documentation samples, and early stage development (before we even have a server).
    Learn about it in the [Http Client](server-communication.html#appendix-tour-of-heroes-in-memory-server) chapter.
    
    ***bootstrap*** - [bootstrap](http://getbootstrap.com/) is a popular HTML and CSS framework for designing responsive web apps.
    Some of the documentation samples improve their appearance with *bootstrap*.
    
  a(id="dev-dependencies")
  
negative.code:   They do not have to be deployed with the production application although there is rarely harm in doing so.
  
    ***[concurrently](https://www.npmjs.com/package/concurrently)*** - 
    A utility to run multiple *npm* commands concurrently on OS/X, Windows, and Linux operating systems.
    
    ***[lite-server](https://www.npmjs.com/package/lite-server)*** - 
    A light-weight, static file server, written and maintained by [John Papa](http://johnpapa.net/) 
    with excellent support for Angular apps that use routing.
    
    ***[typescript](https://www.npmjs.com/package/typescript)*** - 
    The TypeScript language server including the *tsc* TypeScript compiler.
    
    ***[typings](https://www.npmjs.com/package/typings)*** - A manager for TypeScript definition files.
    Learn more about it in the [TypeScript Configuration](typescript-configuration.html#typings) chapter.
    
    This section likely grows as we add more tools, testing, and build support. 
  