Player controlled Golems, Human Colony Rebellion built ships, and Fallen Spire-type frigates don't count towards salvage, being Minor Faction units?
Only units
controlled by a minor faction are exempt. So the resistance fighter guys or marauder guys that do a drive-by from deep space don't leave salvage. But if you repair a golem and lose it outside player territory, or build your own rebel-fighter units from a rebel colony and then lose them outside player territory, or build Fallen Spire capital ships and lose them outside player territory...
Then the AI will get the salvage, and you'll be hearing from it soon.
AI controlled units don't count towards AI salvage, such as Fortresses, correct
If you capture a planet (as in actually put down a command station of your own), and
then kill the AI-controlled fort (or whatever) on it, then you get the salvage. Which wouldn't actually be a bad play, now that I think about it. But if the AI loses a unit it never gets the salvage no matter where it is. Same with you: if the player loses a unit the player never gets the salvage. I had originally implemented and tested it where the AI would get salvage for its own stuff that died outside player territory, and the player would get salvage for the player's own stuff that died in player territory... it's interesting, but way more game-dominating than I wanted. Possibly a toggle for that later would be a good idea, once the core mechanic is stable.
What happens if your AI types are Parasite and Thief?
I'm not exactly sure. Stuff that's reclaimed may or may not create salvage. It probably does, as internally the game "destroys" the unit and then "creates" a new one that looks suspiciously similar.
If the AI physically tractors your units out of player territory and then kills them, it gets the salvage in full carjacking glory.
Finally, an edge case: how do scapegoats and the regeneration golem affect the salvage counter?
Regenerated units are never actually destroyed, so they probably won't create salvage. The scapegoats themselves, when they die via regenerating others, will create salvage. But they're not very high-ticket.