Where do AI Persona cores come from in A18?

[Sola]

I've encountered a handful of exotic goods traders, and killed a bunch of poison and psychic ships, but they don't seem to have them anymore.

[Yoshida Keiji]

http://rimworldwiki.com/wiki/AI_Persona_Core

[Toast]

The wiki page says it can be obtained from exotic goods traders, but it also says it's "only" available from a world quest. Which is it? 

[Sola]

The AI persona core is a highly valuable component used to build the ship computer core, which is one of the ship parts required to get off the planet. It can be obtained from Exotic Goods Traders. Only acquirable by completing the related World quest.

Thanks for the helpful post!

[Snafu_RW]

It's a lot harder to gain than in A17, but in my B18 (1772~) games I've come across it occasionally other than from doing quests/caravanning..

FWIW the new 'cores' introduced by B18 need to be installed (not 'used' like an item)to be activated; once 'installed' they vanish