For all his faults, Voldemort did one good thing for us muggles. He gave us the concept of a horcrux. For the uninitiated, a horcrux is any object in which you store a piece of your soul, putting the proverbial eggs of your soul into different baskets, to gain quasi-immortality.
The basic idea: You split your password into 2 parts - one which is stored in the password manager, and the other which is stored in your head (aka horcrux).
Basically, at any given point in time, you and your password manager know only a piece of the password. It’s double-blind. In effect, just like You-Know-Who, you’re splitting your password (soul) into pieces and storing them in different places.Phani Karan