Don't know if this is a bug or an actual game concept. I keep getting quests (Humble Inns usually, medium level) which require the Exploration Tech.
I have yet to see Exploration show up in the Tech tree of any game I've played. I also don't see Exploration listed in the Hiergamenon.
This goes back to .982. Now I always play a custom Sov - Amarian Warlock, so maybe this choice has blocked this tech.
Just seems too basic a concept to be random or blocked in this way.