Light Side and Dark Side damage types
In KOTOR2 (using the restored content mod, if it matters) there are some items and lightsaber crystals that add bonus lightside damage or darkside damage. There are also a few pieces of equipment that reduce damage from one or both of those types of damage. Other than these rare pieces of equipment that mitigate this damage, what is significant about these damage types?
Do light side damage bonuses deal extra damage to Sith and darkside to Jedi? Also, is Force Lightning an electric attack or a dark side attack? What about Stun Droid?
(This seems to have information on the personal crystal which has different damage types depending on your alignment as well as different amounts of that alignment-elemental damage depending on your foe's alignment: https://www.gamefaqs.com/xbox/920194-star-wars-knights-of-the-old-republic-ii-the-sith-lords/faqs/34505)
Light and dark side aren't damage types per se
There are two different variants:
vs light/dark side
light/dark side
1) refers to the target of the attack/attacker
I.e a weapon with +3 vs dark side damage will do 3 extra damage vs enemies, who are dark side and do no bonus vs neutral oder light side opponents.
Armor with 3 dmg reduction vs light side, will reduce all damage taken from light side opponents by 3 and no reduction vs neutral and dark side.
vs Dark side damage is fairly useful as many enemies are dark side, light side opponents are very rare and only encountered, when you yourself choose dark side. But overall neither bonus is reliable as they don't work vs neutral aligned enemies.
2) grants you this bonus damage on all attacks with the weapon, as long as you are the specified alignment, i.e. +5 light side, means it does +5 dmg, as long as you are light aligned.
Force Lightning is electrical damage.
Light Side and Dark Side Damage are two additional Damage types, just like Energy, Bludgeoning, Cold, etc.
Resistance or Immunity against Energy Damage will not resist Dark Side Damage; only Damage Resistance: Resist #/- vs Dark Side will resist Dark Side Damage.
Similarly, the Hurrikaine Crystal (Crystal, Hurrikaine) deals Unstoppable Damage. Unstoppable Damage isn't inherently irresistible, but nothing provides Resistance or Damage Immunity to Unstoppable Damage.
Force Lightning and Stun Droid both deal Electrical Damage. I had to verify Stun Droid in-game.