This is Perl module Plack::Middleware::DevFilter.
Plack::Middleware::DevFilter installation is straightforward. If your CPAN shell is set up, you should just be able to do
% cpan Plack::Middleware::DevFilterDownload it, unpack it, then build it as per the usual:
% perl Makefile.PL
% make && make testThen install it:
% make installPlack::Middleware::DevFilter documentation is available as in POD. So you can do:
% perldoc Plack::Middleware::DevFilterPlack::Middleware::DevFilter is hosted on github http://github.com/bayashi/Plack-Middleware-DevFilter
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.
Dai Okabayashi <bayashi@cpan.org>