[sudheendrach]

Oops.. you are right. They are using rapportive.

  var LOGIN_URL = 'https://rapportive.com/login_status';
  var LOOKUP_URL = 'https://profiles.rapportive.com/contacts/email/';
  var API_HOST = '104.131.218.68';
  var API_URL = 'http://'+API_HOST+'/api/profiles';

[mkrecny]

How do you access the source?

[illdave]

After installing the extension, open the extensions menu, find it and click "Inspect views: background page", then check the JS file that it references.

[fletchowns]

Any chance you can share the source in a gist or something?