During October 2025, Tkachenko focused on improving file permission handling for Trusted Web Activities in the androidx/androidx repository. He addressed a bug by introducing a read-permission check and conditional write access, allowing applications to perform read-only file operations when write permission is unavailable. This approach aligned the code with Android’s security model, reducing unnecessary write grants and enhancing stability for apps operating in restricted environments. Working primarily in Java, Tkachenko applied his expertise in Android development, file handling, and permissions management to deliver a targeted fix that improved compatibility and reliability for developers relying on constrained file access scenarios.