A major feature absent from the Nintendo Switch since it launched in March has been user's ability to backup and transfer save data. It appears that Nintendo was working on this feature before the console even was released. Nintendo Switch SDK documents leaked to NeoGAF indicate that Nintendo was communicating with developers about two features when the product was still codename NX.
There are two excerpts worth highlighting from the leaked documents.
Nintendo Switch Backup and Transfer Save Data
"In the future, we plan to provide a feature to transfer account save data among multiple consoles. As a result, there is the possibility that user accounts with uninitialized account save data will be added. Note that your design must work without issue, even in this case."
New Nintendo Switch Feature called "Guest Login"
"We are considering a feature in the future (tentative name: Guest Login) to access existing network service account information without linking to a user account. This feature would allow temporary access to the network service account linked to the Nintendo Account by logging in to the Nintendo Account within the application. This feature would, for example, make it possible to upload a character you have raised as online data and then use that data on a friend's NX (without creating a user account).
We do not plan to provide this feature for the NX launch."
The full Nintendo Switch SDK has been leaked to 4Chan, but those were the two most newsworthy morsels to come from the leak.