1 Re "behavior" vs "behaviour", etc.
3 - GNU Emacs originated in the US.
5 - If there is a choice between US vs UK spelling for a word
6 for new text (code, docs), choose the US variant.
8 - It's probably (IMHO --ttn, 2017-10-13) not a high priority to
9 change existing text; use your best judgement (ask if unsure).
11 - http://lists.gnu.org/archive/html/emacs-devel/2005-06/msg00489.html