Your executable appears to output UTF-16le. Decode it. A convenient way for files:

# With LF<->CRLF conversion
open(my $fh, '<:raw:perlio:encoding(UTF-16le):crlf', $fn)
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or

# Without LF<->CRLF conversion
open(my $fh, '<:raw:perlio:encoding(UTF-16le)', $fn)
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