The Four Edges
The Four Edges are a design system for making changes to cards.
Almost any web app you might use today has a way to edit the content. For example, drafting an email, changing a blog article title, editing your user profile - all these tasks required editing tools, yet most developers have to reinvent the wheel each time.
The Four Edges are tools that provide an out-of-the-box way for developers to offer editing capabilities. Those editing tools can be user-facing or can be used to power admin consoles.
Each "edge" refers to a different aspect of data flow in an application. There are environments, networks, libraries, and configurations. Put more simply, navigation, incoming data, available tools, and editing.