on my way throughout the map i found a dead merchant and looted him ...
in his inventory were some more or less useful things and a blueprint worth 3500 (i think it was for new weapons) then a friend asked me if i would join on a counter strike server, i said yes, saved my game and closed kenshi ...
after the game i loaded the savegame and the value of the blueprint dropped to 1000 and it wouldn't teach anything ...
there was nothing in the tooltip except for the new price weight and charges ...
edit: the blueprint for the starting base contains a ore-processor but no stone-processor
i think its a bug, or is it intended to buy thousands of building materials from the stores?