but I have no evidence of NonspacingMark ever being in the normalized string.

There are three in the example you gave: 

use strict;
use warnings qw( all );
use feature qw( say );

use utf8;
use open ':std', ':encoding(UTF-8)';

use charnames          qw( );
use Unicode::Normalize qw( NFKD );

my $html = "Lubomír,Bartoňová";
my $decomposedHtml = NFKD( $html );
say charnames::viacode(ord($_))
   for $decomposedHtml =~ /(\p{NonspacingMark})/g;

Output: 

COMBINING ACUTE ACCENT
COMBINING CARON
COMBINING ACUTE ACCENT

[download]

The code you posted is a hack to find an ASCII "equivalent" to the input.

In reply to Re: Strange Unicode normalization question by ikegami
in thread Strange Unicode normalization question by mje

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