The Information Gathering Tool is to gather emails, subdomains, hosts, employee names, open ports and banners from different public sources like search engines, PGP key servers, and SHODAN computer database. The tool is designed to help the penetration tester on an earlier stage; it is effective, simple and easy to use. The sources supported are: Bing search, Google profiles, LinkedIn, Exalead and PGP servers. New features: Time delays between requests XML results export.”]
Source: https://gbhackers.com/theharvester-information-gathering-tool/