$ git clone -n https://src.fedoraproject.org/rpms/libnbd.git /var/lib/mock/f40-build-1967765-25212/root/chroot_tmpdir/scmroot/libnbd
Cloning into '/var/lib/mock/f40-build-1967765-25212/root/chroot_tmpdir/scmroot/libnbd'...
$ git fetch origin 945d069d3dd3484e0eaf7c2c294573eaa5f8aa08:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libnbd
 * [new ref]         945d069d3dd3484e0eaf7c2c294573eaa5f8aa08 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 945d069 New stable branch version 1.20.2