Squadron chemistry question - "party chemistry trigger rates"

Does anyone know if the chemistry "party chemistry trigger rates increase by ...." means that it modifies the chances of other squad member's abilities activating, or if it means they have a higher chance of getting a new chemistry on mission completion. I always thought it was the latter, but maybe it's the former?

It increases other members' trigger rates on their reward drops by the mentioned amount. It's good to combo with ones that have drops that you want as it makes you more likely to get them.