$ git clone -n https://src.fedoraproject.org/rpms/perl-BDB.git /var/lib/mock/f43-perl-60947730-6586615/root/chroot_tmpdir/scmroot/perl-BDB
Cloning into '/var/lib/mock/f43-perl-60947730-6586615/root/chroot_tmpdir/scmroot/perl-BDB'...
$ git fetch origin c66468ecb2e184614f0ec6191e7f2c2c5b169884:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-BDB
 * [new ref]         c66468ecb2e184614f0ec6191e7f2c2c5b169884 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c66468e Perl 5.42 rebuild