+(use-package projectile
+ :defer 5
+ :bind-keymap ("C-c p" . projectile-command-map)
+ :config
+ (projectile-mode)
+
+ (defun my-projectile-invalidate-cache (&rest _args)
+ ;; ignore the args to `magit-checkout'
+ (projectile-invalidate-cache nil))
+
+ (eval-after-load 'magit-branch
+ '(progn
+ (advice-add 'magit-checkout
+ :after #'my-projectile-invalidate-cache)
+ (advice-add 'magit-branch-and-checkout
+ :after #'my-projectile-invalidate-cache))))
+#+end_src
+
+** [[https://github.com/wasamasa/shackle][shackle]]
+
+#+begin_src emacs-lisp
+(use-package shackle
+ :demand t
+ :commands shackle-mode
+ :config
+ (shackle-mode 1)
+ (setq shackle-rules
+ '(("*Help*" :align right :select t :size 0.5)
+ ("\\`\\*helm.*?\\*\\'" :regexp t :align t)
+ ((compilation-mode "\\`\\*magit-diff: .*?\\'") :regexp t :noselect t)
+ ("*magit-dispatch-popup*" :align bottom)
+ ((inferior-scheme-mode "*shell*" "*eshell*") :popup t))
+ shackle-default-rule '(:select t)
+ shackle-default-size 0.4
+ shackle-inhibit-window-quit-on-same-windows t))
+#+end_src
+
+** [[https://github.com/Wilfred/helpful][helpful]]
+
+#+begin_src emacs-lisp
+(use-package helpful
+ :bind
+ (("C-h f" . helpful-callable)
+ ("C-h v" . helpful-variable)
+ ("C-h k" . helpful-key)
+ ("C-c C-d" . helpful-at-point)
+ ("C-h F" . helpful-function)
+ ("C-h C" . helpful-command)))
+#+end_src
+
+** [[https://github.com/kyagi/shell-pop-el][shell-pop]]
+
+#+begin_src emacs-lisp
+(use-package shell-pop
+ :config
+ (add-to-list 'shackle-rules '("\\*eshell\\*" :regexp t :same t))
+ :custom
+ (shell-pop-universal-key "C-c e")
+ (shell-pop-shell-type '("eshell" "*eshell*" (lambda nil (eshell)))))
+#+end_src
+
+** [[https://github.com/EricCrosson/unkillable-scratch][unkillable-scratch]]
+
+Make =*scratch*= and =*Messages*= unkillable.
+
+#+begin_src emacs-lisp
+(use-package unkillable-scratch
+ :config
+ (unkillable-scratch 1)
+ :custom
+ (unkillable-buffers '("^\\*scratch\\*$" "^\\*Messages\\*$")))
+#+end_src
+
+* Email
+** [[https://notmuchmail.org][notmuch]]
+
+See [[notmuch:id:87muuqsvci.fsf@fencepost.gnu.org][bug follow-up]].
+
+#+begin_src emacs-lisp
+(defvar amin-maildir "~/mail")