This package contains the old version of the FVWM windows manager. It is no longer supported upstream, having been replaced by FVWM 2, and so no non-Debian-related bugs will be fixed unless someone else provides a patch.
You probably only want to use this package instead of the fvwm package if you know what you are doing or have very specific requirements.
FVWM is a fairly small window manager which provides a three-dimensional appearance and a virtual desktop, complete with colour icons.
You will need to install the fvwm-common package if you want the xpmroot command and some icons, along with manual pages for the modules.