$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-Libm.git /var/lib/mock/f41-build-816203-150050/root/chroot_tmpdir/scmroot/perl-Math-Libm
Cloning into '/var/lib/mock/f41-build-816203-150050/root/chroot_tmpdir/scmroot/perl-Math-Libm'...
$ git fetch origin 578a3f3fdf90287ce48455f094b277e35e269b1b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-Libm
 * [new ref]         578a3f3fdf90287ce48455f094b277e35e269b1b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 578a3f3 Perl 5.40 rebuild