$ git clone -n https://gitee.com/mgb01105731/libcxx.git /var/lib/mock/dist-an23-build-540537-84787/root/chroot_tmpdir/scmroot/libcxx
Cloning into '/var/lib/mock/dist-an23-build-540537-84787/root/chroot_tmpdir/scmroot/libcxx'...
$ git fetch origin 72a2dc9ec07c4319afaf507a4770365f8980cd76:KOJI_FETCH_HEAD
From https://gitee.com/mgb01105731/libcxx
 * [new ref]         72a2dc9ec07c4319afaf507a4770365f8980cd76 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 72a2dc9 Update to 17.0.6