Over the years, I have tried various "tasks organizers" and always come back eventually to using a simple text file (lately, using markdown instead of plain text). When writing markdown documents within Atom, my new editor of choice, I can easily preview them as processed documents, which makes it for a more pleasant reading experience. When editing a markdown document with Atom, one can use packages like markdown-folder, to hide various sections; however this does not work in the preview panel, nor does it allow to hide "sub lists".
Since I can easily export markdown documents as html, I decided to write my first Chrome extension to view such documents in a "nice" format, while allowing to hide/show various parts of the document based on the html headings (h1 to h6) or as list items containing other lists, ordered or unordered.
This extension is still very rough around the edges and could definitely be greatly improved upon. It is definitely not in an acceptable state to be uploaded to the Chrome Web Store. For now however, it does the basics of what I wanted it to do and works on any tab for which it has been activated.