Where is the Unity IAP package located?

I’m currently working on an editor script that will ease my transition between freemium and paid versions of my game.I would like to manually import the .unitypackage file that gets imported when I click the import button under Services → In-App Purchasing.

I am aware of the function AssetDatabase.ImportAsset(path) but I need the path of the package first.

Thanks in advance!

I cross posted this to stackoverflow and received an extensive answer there.
Here is the link.