good question! i can answer that lol
In short, it's an in-universe 3DS software that allows the user to view an alternate reality and the events that take place via altering items in a location. This software was made by Juniper during a spirit induced compulsion, meaning she has little understanding of the actual mechanisms involved. Because of this, it is hard to seperate spirits from the mechanism itself, and what influence they could possibly have.
Also a great question! It's a passion project of mine [intended to be a video game] about idea of fate and destiny and what that means. I have a lot of thoughts and feelings about the matter of kismet [if you couldn't tell from my destiny motif], positive and negative. I tend to lean heavily on relationships to display those conflicts, as there are so many facets of fate to consider when you start to look at it. The game follows Juniper and Coda as protagonists, meaning I honestly can't give too much about them here without spoiling a lot of the game [that and it changes freqently]. Related projects exist in the same universe, such as Destiny's Roulette and my persona.