Upgrade action. No functional effect, just an excuse to add fancier models of various furniture/constructions to the game, and even act as a minor sink of resources. Or whatever buzzwords ya'll are using now.
Things like realm cairns, village field cairns, coronation stones, village banners, mineshafts, cupboards, mine supports. Things that have very vital functions, but could have fancier appearances for Jorb to flex all over in Blender.
Prior posts involving this include this terribly titled post and this more specific but better titled thread.