$ git clone -n https://src.fedoraproject.org/rpms/nbdkit.git /var/lib/mock/f40-build-2647278-66693/root/chroot_tmpdir/scmroot/nbdkit
Cloning into '/var/lib/mock/f40-build-2647278-66693/root/chroot_tmpdir/scmroot/nbdkit'...
$ git fetch origin 0e5fe5398b971ac609eb61f189e90a1485da6d0e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nbdkit
 * [new ref]         0e5fe5398b971ac609eb61f189e90a1485da6d0e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0e5fe53 New upstream development version 1.37.13