Lippi’s list of 50

So it seems to be a FIFA rule that each national team manager must submit a mega-list of 50 players that will be available for selection for World Cup qualifying games. I'm unsure about the rules of this list and if/when players can be changed or added (and info about these lists are hard to find, the list was unveiled by a Fiorentina website) but it does show you the players that the national team manager has in consideration.