$value =~ tr/+/ /;
performs transliteration on $value and thus translates characters like !, @, #, etc. to their hex equivalents ... that is, # becomes %23.

No. Assuming there's any point to the code in the first place (see JavaFan's reply), the tr/// transliteration operator does limited character substitution.
     $value =~ tr/+/ /;
transliterates  + plus signs into spaces.

>perl -wMstrict -le
"my $value = '!@#+&*';
 $value =~ tr/+/ /;
 print qq{'$value'};
"
'!@# &*'
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