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Releases are available for Microsoft Windows and Linux. Basilisk includes additional features not found in Pale Moon and carries the Firefox 29-56 era interface ("Australis"). First released in 2017, it was intended as a development vessel for the then-new UXP platform. The Basilisk web browser is Pale Moon's discontinued sibling. 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. The official releases do not support older processors without the SSE2 instruction set. Pale Moon 27.9.4 was the last release to officially support Windows Vista as well as the final community-contributed release for Mac OS X 10.6 Snow Leopard. Two speciality builds continued to support XP for some time: PM4XP, which was discontinued after release 25.7.0, and a special build intended for devices with Intel Atom processors, which was discontinued with the release of Pale Moon 27.0.0. Official support for Windows XP ended with Pale Moon 25.0.0. The name and logo are trademarked by the project founder and cannot be used without his prior permission. To ensure quality, redistribution of officially branded Pale Moon binaries is only permissible under specific circumstances. Pale Moon's source code is released under the Mozilla Public License 2.0 except for parts relating to branding.
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Firefox no longer supports this and retains limited options for UI customization.
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Supports "Complete Themes", add-ons which can customize the entire UI of the browser.Supports extensions built with XUL and XPCOM, which are no longer supported by Firefox.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:
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