Add difftastic

init.el

@@ -424,6 +424,17 @@
   (magit-todos-mode +1)
   :bind (("C-c o g" . magit)))
 
+(use-package difftastic
+  :demand t
+  :bind (:map magit-blame-read-only-mode-map
+         ("D" . difftastic-magit-show)
+         ("S" . difftastic-magit-show))
+  :config
+  (eval-after-load 'magit-diff
+    '(transient-append-suffix 'magit-diff '(-1 -1)
+       [("D" "Difftastic diff (dwim)" difftastic-magit-diff)
+        ("S" "Difftastic show" difftastic-magit-show)])))
+
 (use-package sideline
   :delight
   :hook (flymake-mode . sideline-mode)

packages/packages.nix

@@ -66,6 +66,7 @@ with epkgs; let
       magit
       magit-delta
       magit-todos
+      difftastic
       with-editor
       diff-hl
       corfu