What does the "ship cost on star system" modifier do?

At some places in the game I see a ship modifier of "ship cost on star system", for example the Vaulters' Ylona class (destroyer-equivalent) has an inherent attribute of "-5% ship cost on star system":

What does that modifier do? It sounds like a convoluted way of saying the ship is cheaper to produce, but I tried filling that hull with some modules and comparing it with another class without that attribute (Anjka class, corvette-equivalent) and it shows the same value listed under the ship's "cost".