What is Federated Learning of Cohorts (FLoC)? How will it work?

As third party cookies are leaving our life, Google offers marketers Federated Learning of Cohorts (FLoC) so they can keep optimizing their ad spend. FLoC is a new tracking technology that is planned to be rolled out as third party cookies are banned by Google in 2023. FLoC uses federated learning principles. FLoC creates groups or "cohorts" by using browser historical data of users. Google has just started to test FLoC in 2021 in some countries.