Never mind, I found one.
I think it would do fine for a 15g tank. IME
, most built in skimmers are not very good, I'm not fond of the design I see....but it will probably be fine for your 15, frequent weekly or bi-weekly water changes will maintain waterquality and any benefit from the skimmer will just be bonus. From the pic I saw, there is a place , although it seems small. Possibly on the bottom under the drip area.