Interactivity API needs documentation for its API at https://github.com/WordPress/gutenberg/tree/trunk/packages/interactivity/docs
These are the basic concepts that need to be documented.

• Populate store with an initial state
• Document JS API (view.js)
  • Store
    • State, selectors, actions, effects
• Document directives (grouped by functionality)
  • Declarative function
    • data-wp-interactive
    • data-wp-key
  • State
    • data-wp-context
  • Attributes
    • data-wp-bind
    • data-wp-class
    • data-wp-style
  • Inner content
    • data-wp-text
  • Event handlers
    • data-wp-on
  • Side effects
    • data-wp-effect
    • data-wp-init