-"Update the local keyring with the keys of a key server and removes from the "
-"keyring the archive keys which are no longer valid. This requires an "
-"installed wget and an APT build configured to have a server to fetch from. "
-"APT in Debian does not support this command, but Ubuntu's APT does."
+"Work similar to the <command>update</command> command above, but get the "
+"archive keyring from an URI instead and validate it against a master key. "
+"This requires an installed &wget; and an APT build configured to have a "
+"server to fetch from and a master keyring to validate. APT in Debian does "
+"not support this command and relies on <command>update</command> instead, "
+"but Ubuntu's APT does."