Thanks to Apple blog iphone-ticker.de, Apple have (likely by accident) included the data protection policy for CarKey in the Wallet app on iOS 13.6.
This data protection policy was found on iOS 13.6 inside the Wallet app, where CarKey passes will be kept. iphone-ticker.de also shared the full transcript of the policy, which can be read below:
Wallet allows you to add and share car keys for certain vehicles. You can add a car key by logging into the vehicle manufacturer’s app or entering a coupling code in Wallet to assert your claim as a vehicle owner and to pair your device with your vehicle. If the connection is successful, your device sends a one-time redemption token for the holder to Apple. Apple uses the redemption token, information about your Apple account and device, and your location details at the time of deployment (when location services are enabled) to prevent abuse.
To configure your car key, Apple shares a unique device ID with your vehicle manufacturer. This device ID is different for each vehicle manufacturer to protect your privacy. Your vehicle manufacturer can link this device ID to other information that it has collected about you and will process this information in accordance with its privacy policy.
You can share car keys by tapping “Invite” on the back of the card, selecting the type of access you want, and sharing the card for the car keys using iMessage. Apple shares information about who a card is shared with and the type of access granted to the vehicle manufacturer to help configure and manage cards for car keys. Apple also shares a unique device ID for the card recipient with the vehicle manufacturer so that they can manage your card. For card recipients and owners, the vehicle manufacturer can combine the device ID with other information about the recipient and process this information in accordance with its privacy policy.
Apple does not collect or keep any data about vehicle use, such as when the card for the car keys was used to unlock or lock the vehicle. Your vehicle manufacturer can collect usage data of your vehicle in accordance with the agreements made with you. We recommend reading the vehicle manufacturer’s privacy policy for additional information.
Source: iPhone-ticker.de (Translated from German to English via Google Translate)
It would seem that you will be able to invite other people, such as friends or family members, to gain access to your CarKey in order to unlock your compatible vehicle.
It is likely that Apple will be announcing CarKey at WWDC next week, and CarKey could potentially be launching for iOS 13.6 and not iOS 14 as many leakers have suspected. Considering this was found inside iOS 13.6 and not in any previous version of iOS 13 (e.g. 13.5/13.5.5), it very well could be launching with iOS 13.6.
This is not the first time that CarKey has leaked, and a few months ago, the user interface for CarKey leaked, showing how it will look and work, and even display the model of the car you have CarKey set up for. You can see the leaked UI below:
Credit to iPhone-ticker.de for this information!