$ git clone -n https://src.fedoraproject.org/rpms/rust-lock_api.git /var/lib/mock/f45-build-42990-799/root/chroot_tmpdir/scmroot/rust-lock_api
Cloning into '/var/lib/mock/f45-build-42990-799/root/chroot_tmpdir/scmroot/rust-lock_api'...
$ git fetch origin 50a5eae8e94b5c2caa07862b775e992933d03492:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-lock_api
 * [new ref]         50a5eae8e94b5c2caa07862b775e992933d03492 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 50a5eae Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild