Is a Google sign-in required to be able to use Kmail?

In the initial config of Kmail, I input my email address and password which is not a Google email address. Every time I try it, Firefox opens and I get a login screen for Akonadi Resources for Google Services. Is this required just to be able to use Kmail? Is it required for all other apps that are controlled by the Akonadi database? I’m primarily interested in running KOrganizer. Will I have to login to Google Services just to be able to run a To Do List on my local computer?