Netscape Browser in the context of "Quantum (Mozilla)"

Gecko is a browser engine developed by Mozilla. It is used in the Firefox browser, the Thunderbird email client, and in a discontinued state on AOL's Netscape 6, Netscape 7, Netscape Browser and Netscape Navigator 9; this is alongside many other projects.

Gecko is designed to support open Internet standards, and is used by different applications to display web pages and, in some cases, an application's user interface itself (by rendering XUL). Gecko offers a rich programming API that makes it suitable for a wide variety of roles in Internet-enabled applications, such as web browsers, content presentation, and client/server.