Internet Kill Switch : Who will decide the complete digital blackout on a global scale?

The "Internet Kill Switch", as it is known worldwide, is a protective "countermeasure". It is the ability of governments to restrict or directly block access to the Internet: turn off all servers and connections. Considering all that the Internet entails in our daily lives, it is an extremely powerful weapon. Some consider it as a key tool for national security, allowing governments to respond immediately in times of crisis or cyber-attacks. Others fear a potential abuse of authority, claiming that it infringes on civil liberties and democratic values. Is it possible to implement this measure as a global reconfiguration, and why would it be done?