$ git clone -n https://gitee.com/magic-orange/perl-bignum.git /var/lib/mock/dist-an7_9-updates-build-366088-71186/root/chroot_tmpdir/scmroot/perl-bignum
Cloning into '/var/lib/mock/dist-an7_9-updates-build-366088-71186/root/chroot_tmpdir/scmroot/perl-bignum'...
$ git fetch origin 64aab417f90a3e07dd50cbdb2807317e3eda0571:KOJI_FETCH_HEAD
From https://gitee.com/magic-orange/perl-bignum
 * [new ref]         64aab417f90a3e07dd50cbdb2807317e3eda0571 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 64aab41 spec: add sub doc package