The Department of National Defence would be responsible for that designation, meaning that it would recognize a mission as being a combat mission. As Rear-Admiral Summers indicated, those on one know. Similarly, the special duty service designation is awarded by the Department of National Defence on the recommendation of the chief of the defence staff, a designation equivalent to a higher level would be recommended by the chief of the defence staff to the Minister of Defence.
On October 21st, 2024. See this statement in context.