This is the relevant code for Android 17:
https://gitlab.com/grapheneos/kernel_pixel/-/tree/17-base
https://gitlab.com/grapheneos/kernel_pixel_muzel/-/tree/17-b...
There are other branches there with it for Android 17 QPR1 Beta and Android 17 QPR2 Beta.
Google could save everyone including themselves a lot of hassle by simply publishing it to GitHub. If they don't want to push it to AOSP for weird organizational reasons as part of saying AOSP doesn't support Pixels, fine. Taking weeks or more to get back to us isn't reasonable for one the largest tech companies in the world.
It's also questionable whether what they're providing is truly the preferred form for modification considering the build system is quite unhappy about the lack of Git repositories. They had to provide a repo manifest metadata file to work around part of it.
Pixel 9a and earlier were sold as the official Android Open Source Project (AOSP) reference devices. They made a commitment to providing 7 years of updates for the Pixel 8 and later. Android 16 declared Pixels were no longer AOSP reference devices and stopped providing any support for them. From our perspective, Google hasn't fulfilled their update commitment for the Pixel 6 through Pixel 9a. It's fair to say the Pixel 10 and later weren't sold as AOSP reference devices and didn't have any commitment to providing sources as part of the updates, but that isn't the case for the earlier devices.