$ git clone -n https://src.fedoraproject.org/rpms/rust-vm-allocator.git /var/lib/mock/f40-build-2040640-48371/root/chroot_tmpdir/scmroot/rust-vm-allocator
Cloning into '/var/lib/mock/f40-build-2040640-48371/root/chroot_tmpdir/scmroot/rust-vm-allocator'...
$ git fetch origin 395b81cefd4103391fc5cc2d8a56283efe9bab54:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-vm-allocator
 * [new ref]         395b81cefd4103391fc5cc2d8a56283efe9bab54 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 395b81c Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild