Firas Abd Alrahman

Once you install WordPress with some plugins and finish customizing your theme, you usually stock with performance issues. 
Installing and configuring a good caching plugin, you will enhance your first byte and website speed, but you getting low rank on google page speed. 
The reason for that, each WordPress plugin come with it\’s assets (js/scss files) and most of them are not really used or required, but WordPress does not offer a way to control those injected files in your themes. 
GSP Assets Manager offer an easy way to list, review and control WordPress assets. 
You can disable, move to the header, move to the footer, toggle async for javascript and WordPress without writing a single code. 
The plugin also offer a live preview for CSS, so you can disable the CSS file and see the result directly on your website before you save, to avoid breaking the website style.

GSP Assets Manager (Easy Live Assets Editor)

GSP Assets Manager will allow you to live review and control WordPress javascript files and stylesheets. Optimize google page speed rank within 5 minu …

Kuba Mikita

Just install it and get URL’s working – no coniguration is required.
This plugins fix errors with:
<ul>
<li>CSS</li>
<li>JS</li>
<li>Fonts (also with Google fonts)</li>
</ul>
Also with this plugin you can get rid of “Asset from origin ‘XXX’ has been blocked from loading by Cross-Origin Resource Sharing policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource. Origin ‘XXX’ is therefore not allowed access.”

Polylang assets URLs fix

This plugin properly handles assets URLs when using different domains for each language

GSP Assets Manager (Easy Live Assets Editor) vs Polylang assets URLs fix