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To ensure quality, redistribution of officially branded Pale Moon binaries is only permissible under the project's proprietary redistribution license. Pale Moon's source code is available under the Mozilla Public License 2.0, with exceptions for image assets relating to the branding.
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UXP is a fork of the Firefox 52 ESR platform, created in 2017 to address the imminent death of XUL/XPCOM technology in the Firefox codebase. Moonchild Productions develops UXP alongside Pale Moon. It includes the Goanna layout and rendering engine, a fork of Mozilla's Gecko engine. Pale Moon is built upon the Unified XUL Platform (UXP), a cross-platform, multimedia application base with ancestry in Mozilla code.
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Uses the pre-Australis user interface ("Strata") as carried by Firefox during versions 4-28.Pale Moon has diverged from Firefox in a number of ways: It also continues to support some types of add-ons and plugins that are no longer supported by Firefox, including NPAPI plugins such as Adobe Flash Player, as well as legacy Firefox extensions.
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Pale Moon retains the highly customizable user interface of the Firefox version 4–28 era. The main differences are the user interface, add-on support, and running in single- process mode. Pale Moon originated as a fork of Firefox, but has subsequently diverged. There are official releases for Microsoft Windows, FreeBSD, macOS, and Linux, as well as contributed builds for various platforms. Pale Moon is an open-source web browser with an emphasis on customization its motto is "Your browser, Your way".
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