Endre Sund enhanced the security documentation for the nrfconnect/sdk-nrf repository, focusing on clarifying the semantics of key persistence for lockable KMU keys and aligning maturity notes for TF-M and PSA Crypto. Working primarily with reStructuredText and leveraging his documentation skills, he delivered targeted updates that improved user understanding of key management features and their correct usage. His contributions addressed nuanced aspects of security documentation, ensuring technical accuracy and consistency across related sections. While the work was limited in scope to documentation, it demonstrated careful attention to detail and a clear grasp of the underlying security technologies and their integration points.