I mainly see this guy on Twitter : https://twitter.com/codexeditor

As his actual work is a bit hidden away on Patreon : https://www.patreon.com/codexeditor

Seems to be a kind of smart editor / ToolsForThought / ToolsForDigitalGardeners

Codex is a web-based operating system for knowledge workers.

With Codex you can transform your notes, texts, images, videos, etc., into a multimedia knowledge graph: just highlight text and create bidirectional links, entities, relationships, attributes, events, and more. This is done from a special text editor which not only offers rich text styling but also separates the markup from the text. This means:

  • no text riddled with brackets
  • bidirectional links come built in with aliases
  • unlimited support for collaboration and multiplayer down the track

Spatial reasoning is central to Codex and is enabled through a desktop-like workspace. You can work with text windows, images, videos, tweets, PDFs, websites (via iframes), 3D models, and many visualisations like graph, timeline, etc. You can snapshot these windows and reload them at any point, letting you pick up your knowledge work where you left off.