I am from the Philadelphia area so I am very familiar with GO puff and I am a retail broker as well. Go puff sells convivence products but they also sell alcohol. They may be working on getting some sort of liquor license in the area so that they can distribute alcohol before they start designing the store and stocking merchandise. They are a very large company that is expanding extremely fast so they may have not gotten too opening up this location yet but when they did their market analysis they realized this is a good site to be in long term so they locked up the lease and wait to open up the store.
You probably have seen this done by other retailers before but not realized what is happening. For example, a local grocery anchored shopping center had Salad works in the center but the location didn't work out for Salad works so they closed the store but kept up all of the signage because it is still marketing for them while they are obligated to pay rent.
I would be happy to discuss this further or any other questions you have in the retail space.