I would recommend that you change

$content =~ s/\/\///; ## had to remove // in front
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into

$content =~ s{\A//}{};  ## remove // at the beginning of the json cont
+ent
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... where I used the s{}{} notation to avoid leaning matchstick syndrome (thus avoid escaping the / as \/, ie, leaning matchsticks: see perldoc perlop Quote and Quote-like Operators). I also added the \A beginning-of-string anchor (see perlre, search for "Assertions"), because your regexp would have deleted the first //, whether it's at the beginning, or embedded in important data in your json. If there might be spaces before the //, then

$content =~ s{\A\s*//}{};  ## remove // at the beginning of the json c
+ontent
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