$ git clone -n https://src.fedoraproject.org/rpms/xrotor.git /var/lib/mock/f45-build-39121-732/root/chroot_tmpdir/scmroot/xrotor
Cloning into '/var/lib/mock/f45-build-39121-732/root/chroot_tmpdir/scmroot/xrotor'...
$ git fetch origin 13e2fc2c55fc08cefb20769dd5ffeb28e3a82846:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xrotor
 * [new ref]         13e2fc2c55fc08cefb20769dd5ffeb28e3a82846 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 13e2fc2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild