Custom iBuffer filter for unsaved buffers

ibuffer-unsaved-files.el

(define-ibuffer-filter unsaved-file-buffers
    "Toggle current view to buffers whose file is unsaved."
  (:description "file is unsaved")
  (ignore qualifier)
  (and (buffer-local-value 'buffer-file-name buf)
       (buffer-modified-p buf)))

(define-key ibuffer-mode-map (kbd "/ u") #'ibuffer-filter-by-unsaved-file-buffers)


;; Then you can press </ u> in iBuffer 
;; Note that in Spacemacs you'd have to use <\ u>