The hash code for this object. [...]
Expression ID should uniquely identify the origin of the expression. E.g.
owasp-crs-v020901-id973337 identifies Owasp core rule set version 2.9.1
rule id 973337. The ID could be used to determine the individual attack
definition that has been detected. It could also be used to exclude it
from the policy in case of false positive.
read / write
A representation of the runtime type of the object.