Salt Cathedral is the Wieliczka salt mine, the name in particular referring to the cathedral found within the mine itself. I have chosen that name because it's the most "wondrous" aspect of the mine and more succinctly invokes what is special about it than just "[place name] salt mine". Secondly, I am trying to avoid using direct locality names in wonder names because a wonder can conceivably be built anywhere, so using a specific Polish town to describe it can quickly become nonsensical. As you know, when a civilisation spawns or respawns, or when a city is conquered, some amount of the surrounding culture is converted to the new owner. In the past, this happened by just taking away culture from the old owner and giving it to the old owner, permanently. There were some problems with this though, when a city changes hands frequently it would introduce residual flipped culture from the previous owner that didn't make sense, it could override cultural control of a tile owned by civ C, and the amount of culture from the previous owner was lost forever and couldn't be used for other purposes even though that might have been interesting. Late in 1.16, I changed this so culture conversion is not permanent. For example, if Greece has 100 culture on a tile and Rome 50, and Rome converts 50% of the Greek culture to Roman culture, before the outcome would have been that Greece has 50 culture and Rome has 100. Now, the game still knows that Greece has 100 culture but 50% of that culture are temporarily transferred to Rome. In practice, this has the same outcome of 50 effective Greek culture and 100 effective Roman culture. But now I can dial back the Roman conversion rate to 0% to restore the old situation easily (e.g. Independents conquer the city nearby). I call this "temporary culture conversion". Another neat factor now is that this conversion decays naturally over time, so if you do not start producing your own culture in conquered cities you cannot rely on the converted culture alone. In the context of those recent commits, there were a few small errors in the implementation of this feature that impacted how cultural growth was calculated. Also, the new rules do not perfectly interact with the pre-existing rules yet, and I also fixed a few of those cases.