$ git clone -n https://src.fedoraproject.org/rpms/gram_grep.git /var/lib/mock/f42-build-side-1-3504340-45983/root/chroot_tmpdir/scmroot/gram_grep
Cloning into '/var/lib/mock/f42-build-side-1-3504340-45983/root/chroot_tmpdir/scmroot/gram_grep'...
$ git fetch origin 060f09ccb7856466d8ac7a426d20811df8bfea6c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gram_grep
 * [new ref]         060f09ccb7856466d8ac7a426d20811df8bfea6c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 060f09c Update to 0.9.7 (close RHBZ#2357570)