The Local Storage item via the Tools and the Web Developer menu displays the content of the local storage for a current page.
Also, the embedded source viewer will notify you when the loaded page is not found in the browser cache. This is applicable for the http(s) protocol.
AFAIUI, if you want to view a page content by the same context menu, the next couple steps can help you: Ctrl+A and the View Selection Source. By the way, this item of the context menu will use an external viewer just as his big brother.
The options dialog let you adjust an external source viewer and verify this settings by the Test button.