Generally, “open source” refers to a computer program in which the source code is available to the general public for use and/or modification from its original design. Open-source code is typically a collaborative effort where programmers improve upon the source code and share the changes within the community so that other members can help improve it further. Open source software is free. Some organizations have capitalized off of providing support and modification services for open source software such as RedHat, Inc.
Orca is a free and open source, flexible, extensible screen reader from the GNOME project for individuals who are blind or visually impaired. Using various combinations of speech synthesis and braille, Orca helps provide access to applications and toolkits that support the AT-SPI (e.g., the GNOME desktop, Mozilla Firefox/Thunderbird, OpenOffice.org/LibreOffice and GTK+, Qt and Java Swing/SWT applications).
PyScripter is a free and open-source software Python integrated development environment (IDE) for Windows. It is built in Object Pascal. PyScriper has several features that make coding in Windows more convenient such as drag-and-drop importing from Internet Explorer, find and replace, split view file editing, brace highlighting, on-the-fly code execution. For a more extensive list of features look up the Wikipedia page.
BlueGriffon takes a straightforward WYSIWYG (What You See Is What You Get) approach to web editing, but also manages to include plenty of more powerful features. It is based on the rendering engine of Mozilla Firefox.
You could just use it to type text, insert images, tables, audio files, videos and so on. But there’s also an SVG editor, form design tools, some CSS support, an accessibility checker, DOM Explorer, and more.
BlueGriffon is free but does utilize commercial plugins, so you may find that some features link you to a web store to purchase these plugins.