/dev/ttyUSB0 device is named /dev/ttyUSB1 after a reboot

Hi all, Could you explain for me about lines:
This is the link about it: https://github.com/openhab/openhab/wiki/Serial-Binding

SUBSYSTEM=="tty", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", ATTRS{serial}=="AE01F0PD", SYMLINK+="ttyMySensors"
SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", ATTRS{serial}=="0001", SYMLINK+="ttyCulStick"

https://www.domoticz.com/wiki/PersistentUSBDevices