Here you can view and edit the files (of the selected client) in the ./conf folder (or in the configuration sub folder) or in the ./etc/admin/datawizard folder.
Settings
(1) Buttons top left: Selection of folder.
(2) Selection top right: The selected client. Depending on the configuration, there may be specific subfolders here.
(3) Window left: Use the context menu for file actions.
Blacklists and whitelists for file extensions
See section Blacklist and whitelists for file extensions.