If those pre-compiled binaries aren't based on GPL software, I don't think you'll have much luck getting their sources.
Android's source code is a maze of branches and tags, unfortunately. The change can have been made in the generic cross-device kernel tree, or it could've been a separate module, or it could've been a binary.
Would changes to external closed-source binary files change the kernel image itself? There are kernel modules in that commit but it looks to me like they all come directly from here: https://developers.google.com/android/drivers
Google does provide detailed instructions for downloading all sources for the kernel, and I didn't see any changes since 2023 to any source files: https://source.android.com/docs/setup/
Thanks for the extra places to look. I'll check them out.
Would changes to external closed-source binary files change the kernel image itself? There are kernel modules in that commit but it looks to me like they all come directly from here: https://developers.google.com/android/drivers
Google does provide detailed instructions for downloading all sources for the kernel, and I didn't see any changes since 2023 to any source files: https://source.android.com/docs/setup/
Thanks for the extra places to look. I'll check them out.