This discussion asked the question about what exactly enhanced password protection is as listed in the pricing tier. The answer was:
Enhanced Password Protection refers to breached password detection, and Credential Guard which will let a user know they are using a known leaked password.
Breached Password Detection
However Breached Password Detection is an explicitly named different line item, so I don’t feel like this question has been sufficiently answered. If it’s not password strength policies, and it’s different enough to be a separate line item what exactly is it?