Mail app: what is Apply Rules doing ?

Bomiboll wrote:

In the Mail Settings, you set up ruled. Once you did that, you need not click the Apply Rules.

So it is there just to perplex.

Rules only automatically run on incoming emails. If you want to run a rule on an already received email, or on emails in another location, you would use the "Apple Rules" menu item. Or if you wanted a rule to rerun you would use this menu item.

Runs the rules you have set up. If you've not set up any rules it does nothing