If they know you used this to generate it, yes. Also, the default of only 20 bits of entropy is not nearly enough, IMO. That's only ~1M options. If you're us

If they know you used this to generate it, yes. Also, the default of only 20 bits of entropy is not nearly enough, IMO. That's only ~1M options. If you're using this to generate a password that foolishly gets hashed using something like SHA-256, even a mobile phone from 15 years ago could have it cracked in seconds. A modern CPU would crack it before your finger even let go of the Enter key. Again though, the information above does require that the attacker knows you used this to generate your password. Without that knowledge, the 20+ character passwords it generates are quite secure, especially if you modify them.