* Carlos E. R. (email@example.com) [20170325 15:44]:
the rest is posix
And that is sensible. Note that setting locale for root to posix was done on purpose mainly because sorting behaves according to locale so a regex like [a-z] only works as expected when sorting is done according to posix. Still today many scripts silently assume a posix locale instead of either setting the affecting locale fascet or using something like [::lower::] which Posix introduced for exactly thios case.