This read-write, per-interface flag controls whether mnMacChangedNotification is sent when that specific interface learns a new MAC address, and has no effect if mnGlobalFeatureEnabled is false. An admin enables this selectively on interfaces of interest, such as access ports facing untrusted devices, rather than generating notifications from every port on the switch. For example, setting mnMacAddrLearntEnable to true(1) on a guest-network access port lets the admin get alerted whenever a new device connects there, while leaving trunk ports silent.