$ git clone -n https://src.fedoraproject.org/rpms/perl-Alien-ROOT.git /var/lib/mock/f41-build-787143-13594/root/chroot_tmpdir/scmroot/perl-Alien-ROOT
Cloning into '/var/lib/mock/f41-build-787143-13594/root/chroot_tmpdir/scmroot/perl-Alien-ROOT'...
$ git fetch origin c5d066dccc42efa352a0d8b6d1fd3a27ad886be9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Alien-ROOT
 * [new ref]         c5d066dccc42efa352a0d8b6d1fd3a27ad886be9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c5d066d Eliminate use of obsolete %patchN syntax (#2283636)