View rendered source
View rendered source is a free extension for your Chrome browser that gives you insight into how a website works. You can use this application to gain insight into your own website as well as another owner's digital platform. As the name view rendered source suggests, you mainly get insight into the rendered source.
In practice, this means that you get information that relates to the difference between the source code and the HTML. Thus, you gain insight into how an HTML code is converted into a functioning website. This allows you to recognize and fix any problems. This is important because a functioning website is "rewarded" with a higher position in search results.
So using the view rendered source extension is SEO technically an interesting wonk. This extension is applicable to both desktop and mobile versions of a website.