When true, this rule is configured as a catch-all that matches every packet regardless of any other match criteria configured elsewhere in the same rule row, and the description explicitly states that setting this true makes all the other match fields irrelevant even if they happen to also be populated. An admin typically uses a matchAny rule as the final, catch-all rule within a profile to implement an explicit default action distinct from cienaCesAclProfileDefaultFilterAction, or as a deliberately simple 'block everything on this interface' rule during a lockdown. For example, an admin responding to an active incident on a compromised port might quickly add a rule with this set to true and cienaCesAclRuleFilterAction set to deny, instantly blocking all traffic on that interface without needing to specify any actual match criteria.