It is known that this trial version has appeared about a week after Apple released the first beta of iOS 17.1 and iPadOS 17.1.

Currently, registered developers can opt in for the beta by opening the Settings app
SettingsMoving forward, navigate to the section
Ensure your software is up to date by selectingOpt for the
Enable the Beta Update optioniOS or iPadOS 17 Developer Beta. Note that this process requires an Apple ID linked to a developer account for downloading and installing the beta version.
iOS 17.1 introduces additional options for your favorite songs, albums, playlists, preferred artists, etc., with favorite content added to the Library and used for recommendations. You can easily favorite items via the Now Playing widget.
Additionally, the AirDrop transfer process can now be completed over the internet, eliminating the need for close proximity. Also, devices running watchOS 10.1 can utilize NameDrop when paired with iOS 17.1.
Other new features include notification lights in the Dynamic Island for applicable models and Wallet functionality enabling users in the UK to connect their banks to view balances and transactions.
Explore more: Detailed overview of 9 changes and new features in iOS 17.1 beta 1