The trust values depend on the configuration of GnuPG and the trust model which is used. In the &quot;web of trust&quot; model, it is possible that one or several intermediaries sign a key and this key can become trusted. This is, of course, not perfect, but an approximation.<p>It is true that the usefulness of such indirect links quickly becomes much weaker than a direct link. What the tool tries to solve is to make an assessment for software, where direct signatures are often not practical.