novelWriter
Open source plain text editor designed for writing novels
...It is designed to be a simple text editor that allows for easy organization of text files and notes, with a metadata syntax for comments, synopsis, and cross-referencing between files, and built on plain text files for robustness. The project storage is suitable for version control software, and also well suited for file synchronisation tools. All text is saved as plain text files with a meta data header. The core project structure is stored in a single project XML file. Other meta data is primarily saved as JSON files.