As mentioned in a few other blog posts, UEFI Forum seems to focus only on their Tianocore-based projects, and don’t consider UEFI apps built outside the Tianocore environment (in C, C++, or Rust). I wish they’d create a project that provides bindings for other languages, to be usable outside the Tianocore Build environment, where most developers operate. Here’s another source of external (to UEFI Forum) headers:
https://github.com/justinian/j6-uefi-headers
[…]This is a set of headers for interacting with UEFI as a C++ EFI application. I found the EDK2 headers seemed to be missing some definitions (or perhaps I just hadn’t found the right headers to include), and the GNU-EFI ones to be specific to using GNU-EFI and tended to break when using clang to natively build an EFI application.[…]
Firmware Security 