Specific gameplay question

Radiation damage
Additionally to the normal damage, some weapons have radiation damage. Does the radiation damage applies only to the hull hitpoints? Does the armor needs to be completely gone before radiation does damage to the hull? Is the armor damaged by radiation?

Repair systems - Stacking effectiveness
When installing more than one repair system on a ship, the stacking effectiveness is applied. Does the stacking effectiveness applies to the Repair Rate or to the Repair Supplies? or both?

Tracer Limpet
Fighters are easier to target if a tracer limpet is attached, but for what kind of weapons? all weapons, or only missile-based weapons (like the target painter does)?

Good questions!

Tracer Limpet
Tracer limpets act exactly the same as target painters. This means all missiles fired at a fighter with a tracer limpet attached will hit. It also encourages missiles to select them as a target. It only affects missiles.

Radiation damage
Radiation damage only affects the hull, damaging each module just like an internal hit. It does not affect armor, and armor needs to be gone for radiation damage to be delivered, as do shields. Basically the impact of a radiation weapon has to make it through to the hull to deliver the ‘dose’ of radiation. That dose then continues to work, even if shields and armor since get repaired. This is more obvious in the next patch which shows floating ‘radiation’ damage counters.

Repair systems - Stacking effectiveness
Only the repair rate is affected by stacking, the supplies remain the same.