If the snippet you show indicates that the bit you wish to remove is the outermost level, and it is not embedded within, or alongside other structures, this is one occasion when the greediness of dot-star comes into its own.

#!perl -slw
use strict;

my $body = $1 if join('',<DATA>) =~ m[env\s*{(.*)}$]s;
print $body;

__DATA__
env
{
    "{";
    F
    {
        "'{\"\{"
    }
    g
    {
        '}';
    }
}
[download]

Output

C:\test>244329

        "{";
        F
        {
                "'{\"\{"
        }
        g
        {
                '}';
        }

C:\test>
[download]

Of course, I can imagine any number of scenarios in which this would not work, but in the absence of further info, attempting to compensate for them would simply be guesswork. If you have a better description of the application, I would relish the opportunity to practice my regex skills on real data.

As effective as Parser::RecDescent is for complex grammers, it seems overkill for this application as described. What's the point in having the much vaunted Perl 5 regex engine, if noone is going to learn to use it?

The regex notation is a mini-language of its own. Like any language, it takes time to learn. Like any language it takes practice to master.