Mozilla Firefox GTK+ 3 web browser on Ubuntu 15.10
a GTK+ 3 build of Mozilla Firefox web browser running Ubuntu 15.10 linux
version 42 nightly build https://nightly.mozilla.org/
GTK+, or the GIMP Toolkit, is a multi-platform toolkit for creating graphical user interfaces. Offering a complete set of widgets, GTK+ is suitable for projects ranging from small one-off tools to complete application suites.
GTK+ is written in C but has been designed from the ground up to support a wide range of languages, not only C/C++. Using GTK+ from languages such as Perl and Python (especially in combination with the Glade GUI builder) provides an effective method of rapid application development.
Mozilla Firefox (known simply as Firefox) is a free and open-source web browser developed for Windows, OS X, and Linux, with mobile versions for Android and Firefox OS, by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. Firefox uses the Gecko layout engine to render web pages, which implements current and anticipated web standards.