~/.vnc/passwdis the default location where the VNC password is stored. The password is stored at this location when the vncserver starts for a first time. To update or change your VNC password you should use vncpasswd command. vncpasswd will promt you two times to enter your new password:
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-change-vnc-password-on-linux