This tool is going to check if any URLs from your site are currently listed in a couple of Phishing DBs. If it finds any the tool will let you know if Google has the URL flagged for Social Engineering. It is also going to check the URL you enter to see if it is currently listed in Google’s Malware API, if Google has the URL flagged.

When you submit the tool will query the API to see if the URL is listed and respond with -

null -> The URL/domain is not currently flagged by Google, not in the Safe Browsing API.
MALWARE -> The domain is currently flagged by Google as malicious
SOCIAL_ENGINEERING -> The URL is currently flagged by Google as a SOCIAL_ENGINEERING URL, either "traditional phishing" OR deceptive content - SEE: Social Engineering (Phishing and Deceptive Sites)
UNWANTED_SOFTWARE -> The domain is currently flagged by Google for downloading unwanted software - SEE:Unwanted Software Policy
MALWARE, SOCIAL_ENGINEERING, UNWANTED_SOFTWARE -> You can probably figure this one out (real rare for this to occurr)