Launcher Options (Question)

Just wondering what the GameKey option is for.

Options->Advanced->[Gamekey]

 

Oooo mysterious...

 

I tried to set it to true, false and Monster (to check if entering a name of a modpack that is no longer on the network makes it show in the launcher), as well as setting it to 1 and pressing one after saving the settings, but none worked.

 

Hmm SirWill is going to have to give us more information to decode this secret.