/usr/share/doc/libparse-recdescent-perl/examples/demo_PerlCSV.pl is in libparse-recdescent-perl 1.967009+dfsg-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | #!/usr/bin/perl -w
use Parse::RecDescent;
my $PCSV_parser = Parse::RecDescent->new(<<'EOGRAMMAR');
file: <skip: '[ \t]*'> line(s?)
line: field(s? /,|=>/) "\n" { $item[1] }
field: <perl_quotelike> { join "", @{$item[1]} }
| /((?!,|=>).)*/
EOGRAMMAR
use Data::Dumper;
print Data::Dumper->Dump($PCSV_parser->file(join "", <DATA>));
__DATA__
comma,separated=>values
with,q{a,perl,twist},/to them/
|