Hi,If you need to get the details of the emails clicked from the email marketing module, you can get it from the "clicked" smart button in the form view of the mailingsEmail marketing -> Open a mailing -> Click on the smart button

If anyone clicks in the mail it will be shown in that smart button.

Or if you need to check the function in the code you can search for the function "def set_clicked(self, domain=None):" in the addons mass_mailing module

Hope it helps