$ git clone -n https://src.fedoraproject.org/rpms/libcxx.git /var/lib/mock/f33-build-322500-57969/root/chroot_tmpdir/scmroot/libcxx
Cloning into '/var/lib/mock/f33-build-322500-57969/root/chroot_tmpdir/scmroot/libcxx'...
$ git reset --hard f1bfe5f55f15fc8e835a05dc309e66f1f0d45ad0
HEAD is now at f1bfe5f - Rebuilt for https://fedoraproject.org/wiki/Fedora_33_Mass_Rebuild