Formiko is a reStructuredText and Markdown editor and live previewer.
It is written in Python with GTK4, libadwaita, GtkSourceView and WebKit. Uses
Docutils and m2r2 Markdown parser.

Features:
<ul><li>GtkSourceView based editor with syntax highlighting</li><li>Optional Vim editor support</li><li>Vertical or horizontal window splitting</li><li>Preview mode with auto scroll</li><li>Periodic file save</li><li>JSON and HTML preview</li><li>Spell check</li><li>Linked file opening</li></ul>