in reply to CPAN reverse dependencies

An easy way to get reverse dependencies is to use cpangraph. You'd run it like this:
cpangraph --reverse CGI
It'll produce a svg graph in the current directory. Use your browser to view it. Now, to get to the point where you can run that command, you'll need to install CPANDB::Generator. Then run this:
#!/usr/bin/perl use strict; use warnings; use CPANDB::Generator; my $cpan = CPANDB::Generator->new( cpan => '/root/.cpan', sqlite => '/root/CPANDB.sqlite', )->run;
That will fetch the sqlite database necessary to get the dependencies. It'll take time, so be patient. Next, make sure that your system can handle svg. Here's a bundle that I used, and, trust me, it works. The whole process will take a couple of hours, so hang tight. Then you're good to go.
#!/usr/bin/perl use strict; use warnings; use CPAN; CPAN::Shell->force('install', "Test", "Test::More", "URI", "LWP::Simple", "LWP::Online", "Time::HiRes", "Getopt::Long", "List::Util", "Scalar::Util", "Math::Complex", "Graph::Directed", "SVG::XML", "GD::SVG", "XML::Parser", "XML::SAX", "SVG::Parser", "Pod::Usage", "XML::Twig", "SVG::Metadata", "Class::Date", "Clone", "Image::ExifTool", "Math::Trig", "Readonly", "Template", "Template::Provider::FromDATA", "Test::Kwalitee", "Test::Perl::Critic", "version", "Test::Pod", "Test::Pod::Coverage", "Test::Spelling", "SVG::Calendar", "Statistics::Descriptive", "Tree::DAG_Node", "Math::Spline", "Math::Derivative", "SVG::Graph", "Transform::Canvas", "Data::Dumper", "Config::General", "SVG::Template::Graph", "DateTime", "HTTP::Date", "Compress::Zlib", "XML::XPath", "Math::BaseCnv", "XML::Tidy", "SVG::TT::Graph", "Geo::ShapeFile", "Date::Simple", "XML::Generator::SVG::ShapeFile", "SVG::DOM2", "GD::Text", "UML::Sequence", "IO::String", "Image::Info", "Test::NoWarnings", "Graphics::ColorNames", "Graphics::ColorNames::WWW", "SVG::Sparkline", "Class::Accessor", "Cairo", "Pango", "Params::Validate", "Exception::Class", "Test::Exception", "SVG::Rasterize", "Graph::Easy", "Graph::Easy::As_svg", "Class::Accessor::Fast", "Module::Load", "Module::Pluggable::Fast", "XML::LibXML", "SVG::Convert", "SVGGraph::Pie", "Test::XML", "Algorithm::Points::MinimumDistance", "SVG::Plot", "SVGraph", "Heap", "Graph::Usage");