$ git clone -n https://src.fedoraproject.org/rpms/rust-version.git /var/lib/mock/f45-build-46054-830/root/chroot_tmpdir/scmroot/rust-version
Cloning into '/var/lib/mock/f45-build-46054-830/root/chroot_tmpdir/scmroot/rust-version'...
$ git fetch origin d2b6fda9ba58161167e745b3defceb2d7926014c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-version
 * [new ref]         d2b6fda9ba58161167e745b3defceb2d7926014c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d2b6fda Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild