It would be amazing if we could refer to old/offline players and ability to use all the functions along with.
Current behavior
player('offlinePlayerName') -> null

Would be difficult though, since most functions require internally a ServerPlayerEntity, which is basically an online player.

Maybe fake players with those names could be spawned for those purposes, given they share most info with the real offline players (as a workaround).

I mainly want to work with statistics app, checking if players were fake or real, their inventory, their last pos and stuff like that. If fake players are used, it might fail the the fake player test so the process of filtering out the reals from fakes.
Is there no way to get the data from the playerdata folder ?

Then that looks a bit like #808. Maybe you could move it manually and it may work by renaming to .nbt, but right now there's no way, no. I also think it could be useful to have a way to access it even if it's just as nbt data.