An internal Google Chrome page allows users to see all interstitial warnings or notifications that may be encountered while browsing the web with Chrome.
An interstitial warning page is shown when Google wants to warn or notify a user about a particular risk or concern before a web page is loaded into the browser. For example, if a web page has been flagged as a phishing site, it will display the above warning before allowing you to proceed.
At these warning pages, users can decide whether they want to ignore the warning and proceed, or go back to the previous page they were at.
While researching the recent deceptive mobile billing interstitial coming to Chrome 71, I stumbled onto the internal chrome://interstitials page that allows you to view all warnings that are supported by the particular Chrome version you are using. For example, Chrome 70 will have different warning interstitials than Chrome 71.