$ git clone -n https://src.fedoraproject.org/rpms/rust-owning_ref.git /var/lib/mock/f45-build-43621-804/root/chroot_tmpdir/scmroot/rust-owning_ref
Cloning into '/var/lib/mock/f45-build-43621-804/root/chroot_tmpdir/scmroot/rust-owning_ref'...
$ git fetch origin ad7f15d6e357c95902b447389eac53312564c819:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-owning_ref
 * [new ref]         ad7f15d6e357c95902b447389eac53312564c819 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ad7f15d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild