Repository plugins embedding external file chooser
From MoodleDocs
By making use of the 'object' tag within the return of the 'get_listing' function, Repository plugins are able to embed an external file chooser within the repository panel. This allows for more customisation of the interface, than is allowed by simply returning a list of the available files. The Equella plugin is an example of doing this.
get_listing
TODO: complete this
updating the filepicker
TODO: complete this