This value specifies the MAC address of the target MEP that Eth-test frames are sent to; setting it triggers the test to run, and it reverts to its default value once the test completes, signaling that another test can be started. An admin sets this to the remote MEP's MAC address to kick off a point-to-point Ethernet test toward that specific peer. Seeing this object still holding the target address well after the expected test duration suggests the test hasn't completed, which is worth investigating.