urlscan.io is a service to scan and analyse websites. When a URL is submitted to urlscan.io, an automated process will browse to the URL like a regular user and record the activity that this page navigation creates. This includes the domains and IPs contacted, the resources (JavaScript, CSS, etc) requested from those domains, as well as additional information about the page itself. urlscan.io will take a screenshot of the page, record the DOM content, JavaScript global variables, cookies created by the page, and a myriad of other observations.
Finally, urlscan.io will try to make a verdict whether the scanned website is considered malicious or suspicious. If the site is targeting the users one of the almost 400 brands tracked by urlscan.io, this will be shown in the scan results.