$ git clone -n https://src.fedoraproject.org/rpms/mediawriter.git /var/lib/mock/f45-build-18217-511/root/chroot_tmpdir/scmroot/mediawriter
Cloning into '/var/lib/mock/f45-build-18217-511/root/chroot_tmpdir/scmroot/mediawriter'...
$ git fetch origin 00cd84efc4e0af9839b2c0a3f4061174cfa421e5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mediawriter
 * [new ref]         00cd84efc4e0af9839b2c0a3f4061174cfa421e5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 00cd84e Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild