or a rate limit makes the bot wait and try again, and does not stop the
daemon.
+**********
+ WhatsApp
+**********
+
+The daemon connects to the WhatsApp account of the user as a linked
+device. In the terminal client or in Telegram, the line ``/whatsapp
+status`` shows the link: not linked, linked and connected, or linked and
+disconnected, with the times of the connection. The answer goes only to
+the client that asked, and the line does not go to the agent.
+
+The session is ``whatsapp/session.db`` in the data directory. It gives
+full access to the WhatsApp account, so the daemon refuses the file when
+its mode is not 0600. The shell of the agent runs as the user, so it can
+read the session. If the session leaks, remove the linked device in
+WhatsApp on the phone, and the session stops working. Without the file,
+WhatsApp is not linked. When the session holds a linked device, the
+daemon connects at its start, and after a network failure it connects
+again by itself.
+
*******
Probe
*******