These are all good tools, some even extract the path. But I couldn't find an example of reducing a complex data structure to essential parts.

find_rehohy( $VAR1 );
sub find_rehohy {
    my( $root ) = @_;
    my $my_cb = sub {
        my $val    = pp( $_[0] );
        my $path   = $_[1];
        my $depth  = $_[2];
        my @Paths  = @{ $_[3]||[] };
        my $depthpad = ( " " x $depth );
        my $varname = shift @Paths;
#     print "DiveVal( $varname, qw/ @{[ @Paths ]} /)\n$depthpad = $val
+; #d$depth\n\n";
        use Data::Diver qw/ DiveVal /;
        use Data::Printer;
        if( $Paths[-1] eq 'field' ){
            p( @Paths ); 
            my $reff = 'HASH' eq ref $root ? {} : [];
            DiveVal( $reff , @Paths ) =  $_[0];
            p $reff ;
            return;
        }
        return;
    };
    rehohy( $root,  0=> '$ref->' , $my_cb );
}
__END__
[
    [0] "content",
    [1] "errors",
    [2] 0,
    [3] "field"
]
\ {
    content   {
        errors   [
            [0] {
                field   "merge_fields"
            }
        ]
    }
}
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