Simply, it's an addon where an RTB pref name is placed on to different bricks, and these bricks spawn weapons that have been set for it.
Like you can add a list in the addon(manual) or a chat command to set what weapons are randomly set for each brick.
Or an event that when each time the minigame resets, it randomly selects a weapon or no weapon to spawn on the brick.
Also, RTB prefs if that gun is removed once picked up.