great that there are ways to config this - I might want to change the defaults in some of my projects. Thanks for the tip! 🙂

what is this nil . stuff?

From the (emacs) Directory Variables info page, it's > Instead of a mode name, you can > specify ‘nil’, which means that the alist applies to any mode; or you > can specify a subdirectory (a string), in which case the alist applies > to all files in that subdirectory.

Here's an example of a '.dir-locals.el' file:

     ((nil . ((indent-tabs-mode . t)
              (fill-column . 80)
              (mode . auto-fill)))
      (c-mode . ((c-file-style . "BSD")
                 (subdirs . nil)))
      ("src/imported"
       . ((nil . ((change-log-default-name
                   . "ChangeLog.local"))))))

File and Directory Local Variables are a really cool feature of Emacs, IMHO. :) Read about them and more https://www.gnu.org/software/emacs/manual/html_node/elisp/Variables.html

Agreed; learning about them was a nice tip that made customizing a particular project/directory super easy (and allowed me to clean up my init file, to boot).

project.el is also very decent if you're on a recent emacs version