$ git clone -n https://github.com/xcp-ng-rpms/kernel.git /var/lib/mock/v8.3-incoming-11351-29665/root/chroot_tmpdir/scmroot/kernel
Cloning into '/var/lib/mock/v8.3-incoming-11351-29665/root/chroot_tmpdir/scmroot/kernel'...
$ git fetch origin ac79767f995dc932d7a3cc5aece18bfce70cb9df:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/kernel
 * [new ref]             ac79767f995dc932d7a3cc5aece18bfce70cb9df -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ac79767f9 Merge pull request #24 from xcp-ng-rpms/8.3-import_kernel-4.19.19-8.0.45.xs8.src.rpm