Man pages matching name cgi::application::plugin::devpopup::httpheaders in section 3pm:

CGI::Application::Plugin::DevPopup::HTTPHeaders.3pm.en	debian 10 / libcgi-application-plugin-devpopup-perl
CGI::Application::Plugin::DevPopup::HTTPHeaders.3pm.en	debian 11 / libcgi-application-plugin-devpopup-perl
CGI::Application::Plugin::DevPopup::HTTPHeaders.3pm.en	debian 12 / libcgi-application-plugin-devpopup-perl