Parameters for port.postMessageTo.
Send a message to one port, as a port:message event to that port's window. An unknown sending port fails with PORT_NOT_FOUND, a sending port of another window with PERMISSION_DENIED, an unknown target port with TARGET_NOT_FOUND, and a target window that did not take the event with OPERATION_FAILED.
Parameters for
port.postMessageTo. Send a message to one port, as aport:messageevent to that port's window. An unknown sending port fails withPORT_NOT_FOUND, a sending port of another window withPERMISSION_DENIED, an unknown target port withTARGET_NOT_FOUND, and a target window that did not take the event withOPERATION_FAILED.