If this is marked, the PGP signature of the article is automatically checked when showing the article; if there's no mark, you can check the signature for correctness manually with the View Verify PGP-Signature menu entry.
Se isto estiver marcado, compróbase automaticamente a sinatura PGP do artigo cando se exhibe o artigo; se non hai marca, pode comprobar manualmente a corrección da sinatura coa entrada do menú Vista Verificar Sinatura PGP.