The welcome-document-listing detail of the web-app, is used to outline a listing of welcome documents. Its sub-detail is a welcome-document that is used to outline the welcome document.
A welcome document is the document that is invoked mechanically with the aid of using the server, in case you do not specify any document name.
By default server appears for the welcome document in following order:
If none of those documents are found, then the server renders a 404 error.