$ git clone -n https://src.fedoraproject.org/rpms/xonsh.git /var/lib/mock/f45-build-39004-731/root/chroot_tmpdir/scmroot/xonsh
Cloning into '/var/lib/mock/f45-build-39004-731/root/chroot_tmpdir/scmroot/xonsh'...
$ git fetch origin c2fe0fef7a8e2459ad41aa5018561146121dd823:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xonsh
 * [new ref]         c2fe0fef7a8e2459ad41aa5018561146121dd823 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c2fe0fe Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild