Not much is known about this screen. It is speculated that the number represents the amount of Files need to loaded which include but not limited to Model, Feature, Weapon, Shark, Ship, Currency, System [Timer, Shark Health Bar, Car System, GUI], Scripts [Event Script, Modules, Gun Script, Shark Script, Boat Script, GUI Script, Badge Script] and Sync to load.
The loading speed depends on your internet power and even how long you have left the game.
If high, it instantly goes the the "Welcome the Sharkbite" screen
If low, then the number of files can appear up to 435-450 files to load
The default number when you join is 100 files