A kioslave to display recent documents or URLs in the file dialog, in the file manager, in KRunner and in the Application Menu.

You can use the kioslave like this:

Type recentdocuments:/ in the location bar of Dolphin, Konqueror and the file dialog to list the recently opened documents or URLs.

You can add an entry to the Places sidebar: right click on the sidebar, choose Add Entry, enter recentdocuments:/ in the Location field and save it. It should be available now in all file dialogs unless you check to show the entry only in this application.

In the System Settings module Plasma Search enable the search plugin Recent Documents to use this kioslave in KRunner.

In the Application Menu add a menu item with recent documents at the top of the menu by enabling Show recent documents on the settings page.