Name: Manuskript
Homepage: http://www.theologeek.ch/manuskript/
Open Source: yes
Source: https://github.com/olivierkes/manuskript | http://www.theologeek.ch/manuskript/download/

Description: "Manuskript is a perfect tool for those writers who like to organize and plan everything before writing. The snowflake method can help you grow your idea into a book, by leading you step by step and asking you questions to go deeper. While writing, keep track of notes about every character, plot, event, place in your story."

Manuskript has become stable since the latest update and was hoping to see it be included, so that I don't have to use a VM to run it on Solus as the Flatpak version doesn't work how I'd like it too.