Simply put, a feature to track the time between loads of an offline world, in order to allow for plant and animal time passage effects.
Ideally, this would be an option with a slider from none to full. At none no time would pass. Having increments which slowed the amount of time passed would allow for more choice (think 1/2, 1/4, 1/10) where full would be the equivalent to having the full time passage.
This would be a low priority QOL feature for players working on personal projects without GM commands. It should in no way matter outside of that. This would be nice for some people looking to play the YO version with friends on an occasional basis as well.