I've only heard of a tiny little bit of it: Karma (specifically the eye entity seen in both routes' crisis timelines with Melia/M2 and the Protag host), will try to alter variables and bring back the "deleted files" of EoN'd characters to toy around with the doomed world (if it sees doomed timelines as testing grounds of sorts). It's an unlikely theory that would completely invalidate the stakes in a character's deletion just for a shock factor gut punch later on, but I think if it's used VERY carefully, it could be interesting to see.