You may read the Perl library documentation locally by running:
% fvwm-perllib man <topic>
Available topics:
index
tutorial
FVWM::Commands
FVWM::Constants
FVWM::Event
FVWM::EventNames
FVWM::Module
FVWM::Module::Gtk
FVWM::Module::Gtk2
FVWM::Module::Terminal
FVWM::Module::Tk
FVWM::Module::Toolkit
FVWM::Tracker
FVWM::Tracker::Colorsets
FVWM::Tracker::GlobalConfig
FVWM::Tracker::ModuleConfig
FVWM::Tracker::PageInfo
FVWM::Tracker::Scheduler
FVWM::Tracker::WindowList
General::FileSystem
General::Parse
For example:
% fvwm-perllib man FVWM::Module
Switch to window theme, pager on top theme, navigation theme,
Last modified on April 26, 2010