From within my apex controller, how do set PageReference to redirect to an object's list view page?

The only documented way of doing this is through visualforce:

<apex:page action="{!URLFOR($Action.Account.List, $ObjectType.Account)}"/>

 However, I want to be able to do this from the controller instead:

public PageReference confirm()
{
	// Do prep data
	
	PageReference ref = new PageReference();
	
	// ??? redirect to object's list view

	return ref;
}