watched_channels is a space separated list.
The manager user does not need any write rights, and only needs read=call rights.
Example manager.conf entry:
[pbxnotify]
secret=pbxnotify
deny=0.0.0.0/0.0.0.0
permit=127.0.0.1/255.255.255.255
read=call
Notify pushover.net client on call ringing.
Mutes ALSA channel on call pickup (and unmutes on hang up).