There isn't an archive label.
When you click the archive button gmail removes the inbox label. That's it.
If the message/conversation has no other label, then it will have no attached label. If the message/conversation has one or more labels in addition to the inbox label, then those other labels will remain attached after the archive button is clicked.
Everything except spam and trash is found when you specify "all mail". It shows all the mail. Those messages/conversations can have zero, one, or more labels.
to see all the archived messages with the BOB label show: