The last time that I played was 9 months ago more or less. And I returned to my drug 
. The game has grow in a lot of things (thanks to all you).
And in crafting menu there is a new tab (for me) the “buildings” and I don’t know how can I do with this. I look for it in the wiki but I didn’t find any thing.
I have try with the debug (unlock all recipes) to see some change but the tab is still empty.
Thanks.
There seem nothing there on my end too, unless i have not yet discovered it. 
i think its a placeholder for later entries.
As far as I know it have its use in player-made NPC camps, but never played around with them personally.
In npc camps, i only see manager tabs. ill check it out
This tab should be hidden - it is not intended to be shown in normal crafting process.
The tab should be for NPC use only. It should be hidden from the player. But essentially it’s for NPC base recipes.