Re "behavior" vs "behaviour", etc.

- GNU Emacs originated in the US.

- If there is a choice between US vs UK spelling for a word
  for new text (code, docs), choose the US variant.

- It's probably (IMHO --ttn, 2017-10-13) not a high priority to
  change existing text; use your best judgement (ask if unsure).

- https://lists.gnu.org/r/emacs-devel/2005-06/msg00489.html