Apps to Extensible by Plugins/Extensions

QupZilla is a free and open-source web browser designed for general users, emphasizing speed, privacy, and a clean user interface. It leverages the powerful QtWebEngine to deliver a modern browsing experience while remaining lightweight and resource-efficient.

ImpressPages is an open-source PHP framework and content management system (CMS) designed for building websites quickly and efficiently. It features a user-friendly drag-and-drop interface, a modular architecture, and includes functionalities for blogging, e-commerce, and more. Its framework core provides flexibility for developers.

K-Meleon is a fast, customizable, and lightweight open-source web browser for Windows. Utilizing the Gecko engine from Firefox, it emphasizes efficiency, user control, and a highly adaptable interface, making it ideal for users prioritizing performance and personalization.

MinGW is a minimalist software development environment for Windows, leveraging the GNU toolchain, primarily GCC. It provides a set of freely available and freely distributable Windows specific header files and import libraries combined with GNU tools that allow users to create native Windows applications.

Thunar is a modern, lightweight, and fast file manager for the Xfce desktop environment and other Unix-like systems. Designed for simplicity and speed, it focuses on delivering a highly responsive file browsing experience directly out of the box, while remaining easily customizable through plugins.

Jenkins is a leading open-source automation server that enables developers to reliably build, test, and deploy their software. It supports various version control systems and build tools, making it a central hub for continuous integration and continuous delivery pipelines.

Synapse is a fast and lightweight semantic launcher primarily for Linux, built with Vala. It allows users to quickly launch applications, search for and access files and documents based on usage patterns, and perform various actions via plugins, leveraging the Zeitgeist engine for intelligent searching.

MATE is a classic, lightweight desktop environment that continues the GNOME 2 legacy. It offers a traditional and intuitive interface while providing modern functionality and performance.

MediaWiki is a free and open-source wiki software platform renowned for powering Wikipedia and countless other wikis globally. It provides a robust engine for collaborative content creation and knowledge management, offering a flexible and extensible environment for building information repositories.

muCommander is a versatile, open-source file manager designed for productivity across various operating systems. It offers a dual-pane interface for efficient file operations, built-in support for network protocols like FTP and SSH, and extensive customization options, making it a powerful tool for both casual users and power users who need advanced file management capabilities.

Ajenti is an open-source, web-based server administration panel designed to simplify complex server management tasks. It provides a clean and intuitive interface for configuring services, managing files, controlling hardware, and monitoring server status, making it accessible for both experienced administrators and newcomers.

XChat for Linux is a venerable IRC chat client designed for connecting to IRC networks and participating in chat rooms (channels). It offers support for multiple simultaneous connections, public and private conversations, and a high degree of customization through plugins.

fre:ac is a free audio converter and CD ripper supporting popular audio formats such as MP3, MP4, Ogg Vorbis, FLAC, AAC, and Bonk. It's available for Windows, macOS, Linux, and FreeBSD and is released under the GNU General Public License.

Tomahawk is a free and open-source music player that integrates various music sources, including streaming services, local files, and social networks, into a unified library and playback experience. It allows users to discover, play, and share music seamlessly across platforms.

GIMPshop was a discontinued modification of the free and open-source GIMP image editor, designed to provide a user interface and workflow closer to Adobe Photoshop for users transitioning between the two programs. It aimed to reduce the learning curve for Photoshop users exploring open-source alternatives.

Quicksilver is a powerful and efficient productivity tool for macOS, designed to drastically reduce the time spent navigating files, launching applications, and executing actions. By learning your habits and leveraging a smart, intuitive interface, it allows you to control your Mac with unprecedented speed and flexibility, transforming mundane tasks into effortless workflows.

Apache OpenOffice Calc is a powerful spreadsheet application for analyzing, managing, and presenting data. Part of the OpenOffice suite, it offers a comprehensive range of functions for both casual users and data professionals, providing a free and open-source alternative for handling numbers and lists effectively.

Konqueror is a versatile free and open-source application serving as a web browser, file manager, and file viewer, deeply integrated into the KDE Software Compilation.

Trac is a mature open-source, web-based project management and bug tracking system. It integrates closely with version control systems and provides a wiki for documentation, making it a comprehensive tool for software development teams.

Waterfox is an open-source web browser based on Mozilla Firefox, specifically optimized for 64-bit systems. It prioritizes user privacy, offers extensive customization options, and maintains support for classic Firefox extensions.

Firefox Nightly is the bleeding-edge development channel for the Firefox web browser. It provides early access to experimental features, bug fixes, and performance improvements, allowing users to test and provide feedback on the very latest browser technology before it's released to the public. It's ideal for developers, testers, and enthusiasts who want to experience the future of Firefox.

Bluefish is a powerful yet lightweight code editor designed for web developers and programmers. It offers a wide array of features for HTML, CSS, JavaScript, PHP, and many other programming languages, focusing on efficiency and ease of use for building dynamic websites and applications.

Cinnamon is a free and open-source desktop environment for Linux and other Unix-like operating systems. Developed by the Linux Mint community, it provides a traditional yet modern user interface, blending familiarity with modern design elements for an intuitive desktop experience.

Far Manager is a console-based file manager for Windows, offering a powerful dual-pane interface and extensive customization options. It supports keyboard shortcuts for efficient navigation and file operations, while its plugin architecture allows for significant expandability.

DokuWiki is a popular open-source wiki software designed for simplicity, versatility, and scalability. It focuses on plain text files for data storage, eliminating the need for a database and offering a lightweight, portable, and easy-to-maintain solution for documentation, knowledge sharing, and collaborative content creation.

QEMU (Quick Emulator) is a versatile and powerful open-source hardware virtualizer and emulator. It allows you to run operating systems and programs designed for different architectures on your existing hardware. Acting as a hosted hypervisor, QEMU provides a virtual machine monitor for executing guest systems.

Kate, the KDE Advanced Text Editor, is a powerful yet lightweight text editor popular among developers and advanced users. Offering robust features like syntax highlighting, built-in terminal, extensibility via plugins, and comprehensive customization options, Kate caters to a wide range of text editing and coding tasks across platforms.

HexChat is a free and open-source Internet Relay Chat (IRC) client. Built upon the foundations of XChat, it offers a robust platform for connecting to various IRC networks and participating in real-time text-based conversations, making it a favored choice for users seeking a reliable and customizable chat experience.

Empathy is a versatile multi-protocol messaging client designed for text, voice, and video communication across numerous IM networks. It offers features like file transfers, location sharing, and integration with various services, providing a unified communication experience.

Umbrello UML Modeller is a comprehensive, free, and open-source UML diagram tool. It provides robust capabilities for creating a wide range of UML and other modeling diagrams, supporting developers and designers in visualizing complex systems.