$ git clone -n https://gitee.com/uestc-cheng/libxml2.git /var/lib/mock/dist-an8.8-build-299422-65890/root/chroot_tmpdir/scmroot/libxml2
Cloning into '/var/lib/mock/dist-an8.8-build-299422-65890/root/chroot_tmpdir/scmroot/libxml2'...
$ git fetch origin 74c484fcf5e6938c4f4ca42ad47752696e986650:KOJI_FETCH_HEAD
From https://gitee.com/uestc-cheng/libxml2
 * [new ref]         74c484fcf5e6938c4f4ca42ad47752696e986650 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 74c484f update libxml2.spec.