What does the ‘globalNamespaces’ option in the ‘unplugin vue components’ plugin mean?

Question

Office Doc:

  // Allow subdirectories as namespace prefix for components.
  directoryAsNamespace: false,

  // Collapse same prefixes (camel-sensitive) of folders and components
  // to prevent duplication inside namespaced component name.
  // works when `directoryAsNamespace: true`
  collapseSamePrefixes: false,

  // Subdirectory paths for ignoring namespace prefixes.
  // works when `directoryAsNamespace: true`
  globalNamespaces: [],

But I still don't understand the globalNamespaces option, Can you give me an example? Thank you very much.