$ git clone -n https://src.fedoraproject.org/rpms/libcxx.git /var/lib/mock/f33-build-201807-48101/root/chroot_tmpdir/scmroot/libcxx
Cloning into '/var/lib/mock/f33-build-201807-48101/root/chroot_tmpdir/scmroot/libcxx'...
$ git reset --hard 7f1ea694d444545ae0cb4d2aa190fda73b074d2e
HEAD is now at 7f1ea69 10.0.0 final