Apart from the notes and terminal entries that come with each mini questline. There is a little bit of lore on the terminal in the main building at Black Mountain Ordnance Works.
Black Mountain Ordnance Works is based on a real location called West Virginia Ordnance Works.
Map of all TNT Dome locations
TNT Dome key # 8
Note: You can only obtain the key for this dome when the Invaders from Beyond event is active in the game.
Rewards:
Homer's Aid: Damage vs Aliens +5%
Alien easter eggs
Steps to find the key:
Step 1)
Find "The Emissary".
A little easter egg: The game files refer to this character as "Man in Black".
This character is a random encounter and can only be found in "Scene" encounter locations.
The easiest way to find him is to fast travel to WV Lumber Co in the Toxic Valley and run East along the road until you get to Clancy Manor. If he hasn't spawned for you on one of the red crosses then either wait 18 to 20 mins for the locations to refresh or server hop and run the route again.
Alternatively The Emissary has a chance to spawn at any red dot marker on the map in this drop down.
Step 2)
Unfortunately, the only way to obtain the "Mysterious Key" is to murder him.
I do recommend interacting with him at least once, just to experience another little easter egg.
Note: The mysterious key is not a guaranteed spawn in his inventory, there is a 50% chance that the key will appear. You may need to find and kill him a few times before the key will spawn.
The key can only be used per visit to the TNT dome. To re-enter the dome, you will need to find The Emissary and obtain another key card.
TNT Dome key 8 location:
Fast travel to Black Mountain Ordnance Works.
From the fast travel point, run forward until you reach a T junction.
Turn left and follow the road up, sticking to the right hand side of the road.
Look for the gap in the fence, next to a red sign that says "This area is closed".
Walk through the gap in the fence and keep walking straight until you get to the dirt road. There should be a ruined building in front of and slightly to the left of you.
Turn left and follow the road, past the ruined building and the huge tree stump on your left.
At the end of the road is the dome 8 doors.
Use the ID card reader on the right side of the dome entrance to open the door.
Interact with the screen to reveal some Alien easter eggs and lore.
Don't forget to grab the holotape near the terminal while you are there.
