Elegant Markdown Editor (EME) includes a focus mode, writing without distractions.
ogEditor is a Web-based WYSIWYG HTML editor with a built-in file manager. It features a Tag Selector which lets you view and edit a tag's attributes and internal styles while working in the Design view of an HTML page.
Quill is a free, open source WYSIWYG editor built for the modern web. With its extensible architecture and a expressive API you can completely customize it to fulfill your needs.
StackEdit is a full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites. Read more
XML Configuration File Editor
XML Configuration File Editor (XCFE) is a web service to update the XML configuration file. It allows to set all parameters defined in the CSV configuration files.