This time line system resembles me the multiverse event branches. It is essentially a save game system, with the tracking of snapshots at past time points. It also allows branch a new series of time points. Think of at one point in the past you made another choice, then you have 2 time line of events from then on. Here is what it looks like when you try to load game from it. You choose a save point and load. Most of the time the save will not likely be this complicated with quite some branches. And most likely you will end up deleting useless ones. This is just a demonstration.
When combined with auto saving, this is perfect. Because it tracks your history and if you mess up at one point, you can go back and start a new branch from there. No need to worry about autosave overwriting the previous ones.
When saving, the system can suggest the default save point to be appended. You can also choose your own if you desire. If you try to save to a slot that is not the history of the current game session, it will be treated as overwrite, like that last slot below.
Notice the 2 similar slots in this image, the second one is a clone. You will only want to clone rarely, or clone from an autosave because it creates duplicated history and may confuse you. If you don’t like this kind of saving system, there is the Traditional Mode, which is just like common load/save as you see in other games.
This was yet another backlog in the development system. Cleared.