\s also matches it, but only if perl has the string marked as utf8

As shown below.

use HTML::Entities qw( decode_entities );

my $ch = decode_entities(' ');

print("Unicode Semantics\n");
print("-----------------\n");
utf8::upgrade($ch);
if ($ch =~ /\s/) {
   print("Match\n");
} else {
   print("No Match\n");
}

print("\n");

print("Byte Semantics\n");
print("--------------\n");
utf8::downgrade($ch);
if ($ch =~ /\s/) {
   print("Match\n");
} else {
   print("No Match\n");
}
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Unicode Semantics
-----------------
Match

Byte Semantics
--------------
No Match
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