These scalable icons are taken from the Tango project and are Public Domain.
http://tango.freedesktop.org

apps/dhcpcd.svg is a copy of status/network-transmit-receive.svg

actions/dialog-ok-apply.svg is taken from the KDE Oxygen icon theme
and is licensed under the LGPLv3.

status/dialog-warning.svg is taken from the GNOME icon theme
and is licensed under the GPLv2.

actions/document-new.svg, actions/document-save.svg and
status/network-wireless* are from the Elementary icon theme
by Daniel Foré and are licensed under the GPLv3.