anchor.diff:                            :key #'prompter:value)))
       (prompt
        :input (namestring default-directory)
  +     :default-modes '(file-mode)
        :prompt "Open file"
  -     :sources (list (make-instance
  -                     'file-source
  -                     :actions (list (make-command open* (files)
  -                                      (dolist (file files)
  -                                        (funcall
  -                                         (find-file-function
  -                                          (find-submode
  -                                           (first (old-prompt-buffers *browser*)) 'file-mode))
  -                                         file))))
  -                     :filter-preprocessor #'supported-media-or-directory-filter)))))
  +     :sources (list (make-instance 'file-source
  +                                   :filter-preprocessor #'supported-media-or-directory-filter)))))
  
positive.code: 
  ;; TODO: Separate package?
  (define-mode file-mode (nyxt/prompt-buffer-mode:prompt-buffer-mode)
    "Prompt-buffer mode forthe Nyxt-openable file filtering."
    ((find-file-in-new-buffer t :documentation "If nil, don't open files and directories in a new buffer.")
     (supported-media-types '("mp3" "ogg" "mp4" "flv" "wmv" "webm" "mkv")
                            :type list-of-strings
  
negative.code:            (list "open" (namestring filename))))
      ;; We can probably signal something and display a notification.
      (error (c) (log:error "Opening ~a: ~a~&" filename c))))
  
  (define-command find-file (&key (default-directory (user-homedir-pathname)))
    "Open a file from the filesystem.
  