mail-attachment	 The icon used for an electronic mail that contains attachments.
mail-replied	 The icon used for an electronic mail that has been replied to.
mail-signed	 The icon used for an electronic mail that contains a signature.

network-error	 The icon used when an error occurs trying to intialize the network connection of the computing device. This icon should be two computers, one in the background, with the screens of both computers, colored black, and with the theme's style element for errors, overlayed on top of the icon.
network-idle	 The icon used when no data is being transmitted or received, while the computing device is connected to a network. This icon should be two computers, one in the background, with the screens of both computers, colored black.
network-offline	 The icon used when the computing device is disconnected from the network. This icon should be a computer in the background, with a screen colored black, and the theme's icon element to show that a device is not accessible, in the foreground.
network-receive	 The icon used when data is being received, while the computing device is connected to a network. This icon should be two computers, one in the background, with its screen colored green, and the screen of the computer in the foreground, colored black.
network-transmit	 The icon used when data is being transmitted, while the computing device is connected to a network. This icon should be two computers, one in the background, with its screen colored black, and the screen of the computer in the foreground, colored green.
network-transmit-receive	 The icon used data is being both transmitted and received simultaneously, while the computing device is connected to a network. This icon should be two computers, one in the background, with the screens of both computers, colored green.