Ingenius, thrifty or lazy -take your pick. Above, light "switch" in Pops' blacksmith's shop. Below, leather "pull" on the temporary winter airlock. In its prime the door could swing shut and the latch would slide up onto the keeper and stay closed.
This last was a new one on me but a goody... these old-timey black powder-coated latches clip closed but don't have a lock... that is unless you and your sister are very sneaky and don't like your babysitter, then you can slide a knife through the guide and keeper on your side (the inside) of the door, haha. Good one
Mrs. SugarBob. This stops the latch's handle from being pressed down on the outside and also effectively "bolts" the door.