ah, i think i understand your confusion

support weapons are a type of stratagem (you can see other support weapon stratagems here ) unlike normal weapons, such as primary, secondary, or throwable weapons, support weapons are stratagems that are selected before each mission alongside three other stratagems. you can then call them down using their respective stratagem code, and they will arrive in a manner similar to a resupply or like the machine gun support stratagem in the tutorial.