What is the difference between “%X” and “%x” in following the functions?!
(defvar insert-time-format "%X"
"*Format for \\[insert-time] (c.f. 'format-time-string').")
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(defvar insert-date-format "%x"
"*Format for \\[insert-date] (c.f. 'format-time-string').")
Obvious, if you see the description for insert-time-format you will see that:
%x is the locale’s “preferred” date format.
%X is the locale’s “preferred” time format.