$ git clone -n https://gitee.com/uestc-cheng/libxml2.git /var/lib/mock/dist-an8.8-build-299412-65890/root/chroot_tmpdir/scmroot/libxml2
Cloning into '/var/lib/mock/dist-an8.8-build-299412-65890/root/chroot_tmpdir/scmroot/libxml2'...
$ git fetch origin d71ec75e5af34a01e14c90f3d8c12e6d740c6578:KOJI_FETCH_HEAD
From https://gitee.com/uestc-cheng/libxml2
 * [new ref]         d71ec75e5af34a01e14c90f3d8c12e6d740c6578 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d71ec75 update libxml2.spec.