$ git clone -n https://src.fedoraproject.org/rpms/nbdkit.git /var/lib/mock/f40-build-2350338-60166/root/chroot_tmpdir/scmroot/nbdkit
Cloning into '/var/lib/mock/f40-build-2350338-60166/root/chroot_tmpdir/scmroot/nbdkit'...
$ git fetch origin d89cffce88b1c4da4944fa85951166e4f5cbbbad:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nbdkit
 * [new ref]         d89cffce88b1c4da4944fa85951166e4f5cbbbad -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d89cffc Temporary workaround for binutils bug https://sourceware.org/bugzilla/show_bug.cgi?id=31283