Eitri Shopping exposed APIs are collections of functions complementary to those availaible in Eitri Bifrost exclusive to Eitri Shopping apps that allow an eitri app to call native code to perform a multitude of operations, such as using the mobile device's camera, manipulating the navigation backstack, sending logs to Firebase, among others.
Provided that you already imported Eitri Bifrost, accessing the exposed APIs is just a matter of calling the exposedApis property, followed by the API's namespace and the specific method you wish to invoke.
For example, this is how you would use the logEvent method from the Firebase exposed API:
await Eitri.exposedApis.fb.logEvent({eventName: "event", data: {key: "value"}})
Here, the namespace for the Firebase exposed functions is 'fb', and the method that was called from this group of functions is logEvent