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Since official support for Linux was dropped by Songbird in April 2010, Linux-using members of the Songbird community diverged and created the project. By contrast to Songbird, which is primarily licensed under the GPLv2 but includes artwork that is not freely distributable, Nightingale is free software, licensed under the GPLv2, with portions under the MPL and BSD licenses.
Nightingale has not seen a new release since 2014 and most, if not all, Nightingale developers are no longer actively contributing to its development.
Notable features
Plugins compatible with Songbird (with one modification to the addon)
Users can add features and change functionality in Nightingale by installing extensions. Extensions are similar to the Extensions for the Firefox browser and can be easily ported. Community coded extensions are available on The Nightingale Addons PageArchived 2020-09-29 at the Wayback Machine.
Skins
Skins are referred to as "feathers" in Nightingale, and give users and artists the ability to change the look of Nightingale via an extension which generates a default skin. Using CSS (and optionally XUL), and an image manipulation program such as Photoshop or GIMP, users are then able to make Nightingale look however they want.
Nightingale 1.8.1 on Linux