May 2025 monthly summary focusing on key accomplishments. Delivered backend extensibility improvements for Functorch in the pytorch/pytorch repository by enabling PrivateUse1 support. This involved adding DispatchKey::PrivateUse1 to core functions, allowing tensors to utilize this backend and improving compatibility with third-party backends. No major bugs reported this month; stability and interoperability improvements across backend dispatch paths. Overall impact includes expanded backend compatibility, enabling broader hardware and backend experimentation, and laying groundwork for future private/custom backend integrations. Demonstrated strong backend engineering, C++ core changes, DispatchKey management, and thorough testing/validation across Functorch and core PyTorch components.