Basically it is just a database of games and the results for those games. So, if you found a line where white had 100% win, then there were likely very few games from that position (or you were on the database of your chess.com games).
Basically, the explorer here has a number of master level games and you can see how the games played out. The reason why a particular side won, may or may not have any bearing at what the position looked like at a particular position and is likely impacted by later imprecise play or blunders.
I'm new to chess.com and in my first game I noticed there was something called game explorer. It seems like it shows common opening moves with percentages of win for white, for black or a draw. Some moves are 100% win for one side very early in the game and I find it absurd that this occurs. can someone explain to me exactly how this tool works and how to use it?