To enable applications and software functionality specific to a vehicle context the MeeGo IVI software stack needs to implement an API that allows applications to access vehicle data and execute operations. The MeeGo IVI software stack essentially extends MeeGo Core and consequently the IVI APIs are extensions of the MeeGo Core APIs.
The API most likely will have multiple layers abstracting applications from the underlying specifics of the vehicle architecture. The latter will definitely differ from make to make and most likely within model lines of the same make and also between generations of the same model of a particular make.
The API layer provides vehicle data in a generalized form through methods such as getVehicleSpeed(), getFuelLevel(), getAverageFuelConsumption() etc. as well as executing function such as setRadioTuner(band, frequency), turnOnHeadlights(), lockDoor(doors), etc. An application can make use of these APIs directly.
Another layer of abstraction is the application framework layer that combines operations across multiple MeeGo APIs. An example could be a function providing range information based on the fuel level, the average consumption and the current vehicle position.