Each Freelancer ability has it's own unique list of mods from which the player may choose to assign to it. These mods augment the ability in some way and allow each player to have a custom play style that suits them. Mods also allow counter play when chosen specifically to counter enemy Freelancers.
Each ability can be used without a mod or you can assign exactly 1 mod to it. The mods vary in cost, from 1 to 3 points, and you can assign a cumulative of 10 points worth of mods across all abilities for a single loadout. The default mod for each ability (i.e. the mod that comes equipped with the Freelancer) costs 2 points and there are 5 abilities, totaling to 10 mod points.