$ git clone -n https://src.fedoraproject.org/rpms/perl-Filesys-Df.git /var/lib/mock/f45-build-23626-598/root/chroot_tmpdir/scmroot/perl-Filesys-Df
Cloning into '/var/lib/mock/f45-build-23626-598/root/chroot_tmpdir/scmroot/perl-Filesys-Df'...
$ git fetch origin 065875e246254113c413b82e15320036e66e67a1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Filesys-Df
 * [new ref]         065875e246254113c413b82e15320036e66e67a1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 065875e Perl 5.44 rebuild