Comment 2 for bug 1190676

An auto refresh timer checks every 3 seconds if the current path has been modified since last modification, if so reads the directory and compares it with the current content.

This feature is disabled by default since the plugin is used by other applications like Music App.
To enable that in the UI:
          enableExternalFSWatcher: true

Files added/removed and modfied (size, modification time and permissions ) by other applications are refreshed.

Main code: file dirmodel.cpp
http://bazaar.launchpad.net/~ubuntu-filemanager-dev/ubuntu-filemanager-app/plugin/view/head:/folderlistmodel/dirmodel.cpp#L1060
http://bazaar.launchpad.net/~ubuntu-filemanager-dev/ubuntu-filemanager-app/plugin/view/head:/folderlistmodel/dirmodel.cpp#L1301

Main code: file iorequest.cpp