use strict;
use warnings;

use LWP::Simple;
use Encode;

#I have confirmed the correct HTTP header sent here
my $html = get('http://-redacted-/file.utf8.html');

print "utf8: " . utf8::is_utf8($html) . "\n";
#Output is utf8: 

my $html2 = decode('UTF-8' => $html);

print "utf8: " . utf8::is_utf8($html2) . "\n";
#Output is utf8: 1