jwm binary package in Ubuntu Focal armhf

 Low resource Window manager ideal for older PCs. It uses a minimum of
 external libraries, thus very little memory, includes virtual screens,
 menubar and root-menu popup.
 .
 JWM is a window manager for the X11 Window System. JWM is written in
 C and uses only Xlib and (optionally) the shape extension and libXpm.
 It can support some MWM, GNOME, and WM Spec hints. The menu configuration
 files are managed in XML format.
 .
 Compared to other light WM, like FVWM or Openbox, the Jwm consumes
 considerably less memory while providing the same functionality.

Source package