It adds the NPM package to the <code>"devDependencies"</code> list in your <code>package.json</code> file.
These are the packages your application needs when it is running in the development environment.

It adds the NPM package to the `"devDependencies"` list in your `package.json` file.

These are the packages your application needs when it is running in the development environment.

It adds the package to the <code>"devDependencies"</code> for your application.

 It adds the package to the `"devDependencies"` for your application.

I've seen the npm install <code>--save-dev</code> command used in several different places, but can't figure out what the <code>--save-dev</code> option does.

What does the --save-dev option do when running npm install?