What does defunding the police do?

In its most common form, it’s more about shifting a significant amount of funding away from armed LEO focused on arresting people and using violence or the threat of violence to enforce the law. The money and focus instead could be used for civilian employees for such tasks as responding to traffic collisions, or trained medical/social workers to respond to disputes and mental illness episodes. It would give a wider variety of responses to meet different needs while encouraging cooperation from members of the public who fear the police.