$ git clone -n https://src.fedoraproject.org/rpms/vim-trailing-whitespace.git /var/lib/mock/f40-build-2044791-48744/root/chroot_tmpdir/scmroot/vim-trailing-whitespace
Cloning into '/var/lib/mock/f40-build-2044791-48744/root/chroot_tmpdir/scmroot/vim-trailing-whitespace'...
$ git fetch origin bca171e18bf333f06204f350d1cbb91b38279efd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/vim-trailing-whitespace
 * [new ref]         bca171e18bf333f06204f350d1cbb91b38279efd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bca171e chore: Update to latest git snapshot