An expressive interface is a user interface element whose specific creative presentation may be protected by copyright. This can include original visual or textual choices-such as artwork, icons, or distinctive screen layouts-rather than the underlying idea or function the interface communicates.
In software reimplementation, reproducing a feature’s behavior is different from copying its expressive presentation. A developer may create a compatible function using original design, while reproducing distinctive interface details can raise copyright concerns. Security teams evaluating alternative software should also test it safely: visual similarity or compatibility does not establish how it was built or whether it handles data securely.