Why does Magento 2 new theme from scratch has many js files included?

[Ahmadoooo]

I am just beggining to learn Magento and would like a thougrogh explanation if possible.

I just created a new theme from scratch with NO parent theme, and I found many JS and two CSS files included by default.

Here is a sample:

<link rel="stylesheet" type="text/css" media="all"
      href="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/mage/calendar.css">
<link rel="icon" type="image/x-icon"
      href="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/Magento_Theme/favicon.ico">
<link rel="shortcut icon" type="image/x-icon"
      href="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/Magento_Theme/favicon.ico">
<script type="text/javascript"
        src="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/requirejs/require.js"></script>
<script type="text/javascript"
        src="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/mage/requirejs/mixins.js"></script>
<script type="text/javascript"
        src="http://192.168.1.9/magento/pub/static/version1495681460/_requirejs/frontend/btata/themeone/en_US/requirejs-config.js"></script>
<link rel="stylesheet" type="text/css" media="all" href="http://192.168.1.9/magento/pub/media/styles.css">
<script type="text/javascript" charset="utf-8" async="" data-requirecontext="_" data-requiremodule="jquery"
        src="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/jquery.js"></script>
<script type="text/javascript" charset="utf-8" async="" data-requirecontext="_"
        data-requiremodule="jquery/jquery.mobile.custom"
        src="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/jquery/jquery.mobile.custom.js"></script>
<script type="text/javascript" charset="utf-8" async="" data-requirecontext="_" data-requiremodule="js/responsive"
        src="http://192.168.1.9/magento/pub/static/version1495681460/frontend/btata/themeone/en_US/js/responsive.js"></script>

My questions are:

1- Do I have to keep those files?

2- If not, how to remove them?

3- See attached image, why there are missing files?

Thanks
Ahmad

[rdobbins90989b]

This is a question I have asked many times.

Ultimately the answer is "that's just how Magento is built". To me, a web developer of many years, it seems insane to build a platform this way, and it causes lots of performance issues.

There is no way to reduce the number of JavaScript files without completely re-writing Magento's whole frontend. For example, the Magento_UI module alone uses over 60 JavaScript files.

You can enable JS Bundling but this will force your visitors to download a very large JS file of several megabytes so I don't like that solution either.

Related: https://magento.stackexchange.com/questions/270553/is-it-possible-to-drastically-reduce-the-number-o...

[dashalbelvb2c4]

I also created a custom theme for my website, and when I studied the process of creating it, I came across this tutorial: https://belvg.com/tutorial/magento-2-certified-professional-front-end-developer-guide.
I guess the answer to your question is in section 1