tl;dr: Outer Shell is an open-source graphical shell for SSH where each app runs as a tiny HTTP server communicating over Unix domain sockets, with SSH handling encryption instead of the apps themselves. The shell provides a home screen and inter-app APIs (e.g., registering a text editor for file-opening), supporting both HTML web apps and native "outerframe" apps. The author argues this fills a long-overlooked gap—remote servers getting proper graphical shells rather than ad-hoc per-app web UIs like Jupyter or Tensorboard.