In the iTunes Connect FAQ there's this about tracking campaigns in the StoreKit API:
Can I use the StoreKit API to track campaigns?
Yes. Just add the campaign token and your provider token into the API. You can find more detail on how to do this in the StoreKit Framework Reference.
To get your provider token, generate a campaign link in App Analytics. You can choose your own campaign token, which can be up to 40 alphanumeric characters long, and include punctuation.
The link goes to the doc page for SKStoreProductViewController which doesn't seem like the right place to be going.
I'm trying to figue out how I can access the campaign data in my app? The only thing in the docs that look close is SKStoreProductParameterCampaignToken but I'm unclear of how to use it.