The Sloane-class Stealth Destroyer was a variant created upon the promotion of Xoia Reyes to her own command of a specialized covert unit. Out of all the ships utilized by the First Order, the Sloane-class Destroyer proved to be the best option due to its offensive and defensive capabilities. However, due to the role Reyes and her team would provide, the ship would need to be a bit faster as well as gain some stealth functions to allow for easier covert drops. To help accommodate this, nearly half the weapons were given up to boost its speed and to allow enough power to be directed to its newly added stealth field generator, though still keeping enough firepower to retain its destroyer classification. With these changes, it was able to retain its 12 starfighter and 50 troop capacity.
Upon seeing the success of the new variant, it was created as an open ship for all within the First Order to utilize beside its more powerful older brother.
Running off the idea of Kylo’s Silencer that considered it a stealth field generator that masks itself on sensors. Since then I’ve just referred to anything stealth based that wasn’t a cloaking device as the stealth field generator and cloaking device for that use.