Web Inspector allows you to inspect not just resource files, but also network data, storage values, and hidden properties in your web content. The Elements, Resources, Network, and Storage tabs allow you to view this data. Each tab also has inspection tools to make it easier to filter and navigate to specific pieces of this data.
Elements tab: Lets you view the HTML and CSS files for web content currently displayed in Safari. You can select the HTML for an element and navigate the HTML to focus on specific sections. In the sidebar, you can also view the computed CSS and currently applied style rules, view node properties for an element node, and see additional information about layers .
Resources tab: Lets you view resource files and see the metadata associated with each file.
Storage tab: Lets you see all cookies and values that are locally stored and filter local storage values.