This is TURBO LANZER - the total overhaul modpack for X4:Foundations.
On this short clip you can see what TURBO LANZER means in practice: a destroyer has multiple weapons pods of many sizes (in vanilla ship can use only their dedicated size, M ship, Medium weapons, etc), have a lot more turrets.
Some destroyers - classified as medium ships - have special advantages, for instance Ronin class destroyer has mount for a Large Turret, usually reserved for at least cruisers.
Victory class destroyer - belonging to TRF (The Renaissance Federation) can equip Large size engine, instead of his dedicated M size. This gives enormous speed (that's TURBO), but ships may be hard to handle.
Some fighters - small sized ships - can use medium size weapons (that's LANZER).