After a few months of coding on my own, I decided to release Manuskript. It’s still very much a work in progress, yet it can already be used.
I believe it may help fill the void for open-source tool for writers. As will be evident, it is heavily inspired by Scrivener (though I never ran a version of Scrivener, only saw some screen-shots and screen-casts), but not only. Among other things, Manuskript may help you take advantage of the Snowflake method, develop plots using well-known screenplay models, create references and quickly find informations about specific place or character, etc.
Please have a try, and let me know what you think of it !