5 is the severity level which means everything between 0 and 5 is logged.
The facility value is used to calculate the priority value of the message which is done by below formula:
Priority value = (facility value* 8) + severity value
These are the facility values:
LOCAL0 (Code = 16)
LOCAL1 (Code = 17)
LOCAL2 (Code = 18)
LOCAL3 (Code = 19)
LOCAL4 (Code = 20)
LOCAL5 (Code = 21)
LOCAL6 (Code = 22)
LOCAL7 (Code = 23)
