NodeJS and client-side Javascript in Ember application

I am working on developing a client-side application built on EmberJS.

Now, while I test the code in the browser ultimately, I have the following locally for development;

1. NodeJS & NPM
2. I have defined bower.json & package.json
3. I use ember-cli & do ember build & ember server to start the local server
4. I hit the URL http://localhost:4200 in the browser to access the app

Now my question is I wanted to understand, what exactly is happening here ? Meaning what exactly happens before code runs in the browser.

I understand when the build happens, it actually pushes code into the 'dist' directory.

Is there any role in NodeJS in all of this (meaning any JS run on server-side in the background) OR we just utilize npm/bower for this case ?

So I just wanted to connect all the dots regarding running in the browser.