$ git clone -n https://src.fedoraproject.org/rpms/perl-B-Compiling.git /var/lib/mock/f41-build-816442-150177/root/chroot_tmpdir/scmroot/perl-B-Compiling
Cloning into '/var/lib/mock/f41-build-816442-150177/root/chroot_tmpdir/scmroot/perl-B-Compiling'...
$ git fetch origin c0eb97364a56b1bf57a03ac3bcb72c32058aa11a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-B-Compiling
 * [new ref]         c0eb97364a56b1bf57a03ac3bcb72c32058aa11a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c0eb973 Perl 5.40 rebuild