$ git clone -n https://src.fedoraproject.org/rpms/perl-File-MMagic-XS.git /var/lib/mock/f43-perl-60949791-6586659/root/chroot_tmpdir/scmroot/perl-File-MMagic-XS
Cloning into '/var/lib/mock/f43-perl-60949791-6586659/root/chroot_tmpdir/scmroot/perl-File-MMagic-XS'...
$ git fetch origin ea72d42f12f09accbe4a6669374401bab77cfbc8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-File-MMagic-XS
 * [new ref]         ea72d42f12f09accbe4a6669374401bab77cfbc8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ea72d42 Perl 5.42 rebuild