This spike implements Paypal preapprovals which are currently part of the depricated MPL library. They have not yet been replaced in the new APIs.
The PayPal Mobile Payment Libraries (MPL) provides a secure, extensible, and scalable way to add PayPal functionality to your native mobile apps. Using MPL, you place a Pay with PayPal button in your app's payment flow, which lets customers use their PayPal accounts for payment transactions. MPL completely integrates the payment flow into your app, and customers complete their checkouts without needing to open a webview to process the payment...