"\x{E4}" =~ /\w/

##</code><code>##

#               | the UNIX pipe transports bytes, not
#               | codepoints. So Perl sees the byte E4
$ echo -e "\xE4"|perl -wE 'say <> ~~ /\w/'
#                                 ^^^^^^^ a text operation
#                                 sees the codepoint U+00E4