K-Meleon is an extremely fast, customizable, lightweight web browser based on the Gecko layout engine developed by Mozilla. K-Meleon is Free, Open Source software released under the GNU General Public License and is designed specifically for Microsoft Windows (Win32) operating systems. 2010-12-12: K-Meleon 1.6.0 Beta2 was released. 2010-03-05: K-Meleon 1.5.4 was released.