An icon from gnome-themes-extras-0.9.0.tar.bz2 (specifically Nuvola/icons/scalable/emblems/emblem-important.svg) by David Vignoni.

Modified to look more like the PNG file by Bastique. Recolored by _→AzaToth.

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  Gtk-dialog-warning.svg
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  Nuvola_apps_important_square.svg
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  Nuvola apps important yellow.svg
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  Nuvola apps important.svg
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  Icon_Now_Commons.svg
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  Icon_Now_Commons_orange.svg
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  Under construction icon-blue.svg
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  Laff_alert.svg
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This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See version 2.1 and version 3 of the GNU Lesser General Public License for more details. http://www.gnu.org/licenses/lgpl.htmlLGPLGNU Lesser General Public Licensetruetrue