This is a statistics page for the site audit. The graphic shows the number of errors and warnings found on your website, along with the percentage of your site affected by them. It also indicates how many 404 errors there are, and how many files have been crawled by Google. Site Audit will also show you which errors are found most often and what operating system you users are accessing your site from. This helps you determine where to make changes in order to improve your website's performance overall.