A place holder is a temporary object or device that stands in for something else until the real or final thing is ready or available. It holds the spot or represents the idea, but is not the actual thing. Full definition
Some mundane «chess» puzzles also break up the pace, but to my disappointment the chess pieces are merely place holders for an unrelated puzzle. (playstationlifestyle.net)
To meet all three needs, the areas of expertise section is set up as place holders. (theladders.com)
It could be possible that these two level slots were mere place holders in case they were going to make / waiting for confirmation on these last two level packs. (brickstolife.com)