The code can be found here:
https://kernel.ubuntu.com/git/kernel-ppa/mirror/ubuntu-oem-5.10-focal.git/tag/?h=Ubuntu-oem-5.13-5.13.0-1007.7

And the /usr/lib/debug/boot/vmlinux-5.13.0-1007-oem file can be extracted from here:
http://ddebs.ubuntu.com/pool/main/l/linux-oem-5.13/linux-image-unsigned-5.13.0-1007-oem-dbgsym_5.13.0-1007.7_amd64.ddeb

Also also needed the latest code from https://github.com/crash-utility/crash.git
(at commit f53b73e8380bca054cebd2b61ff118c46609429b)