TKey Unlocked is a non-programmed TKey.
TKey Unlocked can be used for a customer to program a TKey by themselves and by that have full control of what the TKey contains. This will essentially make such a TKey a user owned USB security key.
Another use case for TKey Unlocked is for developers to experiment with the hardware and/or firmware. The heart of the TKey is a Lattice iCE40UP5K FPGA. TKey Unlocked can be used for experimenting with the FPGA.
All information on how to program TKey Unlocked can be found in the Developers Handbook.
NB 1: A TKey Programmer is needed for programming the TKey Unlocked.
NB 2: App development does not require TKey Unlocked, the TKey is sufficient.