IndieGala Golden Flash Giveaways Question

Hi folks. Some giveaway descriptions here alerted me to the IndieGala Golden Flash Giveaways. I was/am not very familiar with these, so I don’t know how long they’ve been going on, or how long they will go on. What I really want to know, though, is how folks can see which game a key is for before redeeming the key. That is, how did you know whether you already had the game, whether you would want to post it here, etc.? All I can see is “Golden Flash Giveaway” and a Steam key code. I am using a Mac, if that is significant.