We will continue to use the existing XML, actually JWM menu specifications in all extensions.
Each window manager that can support a menu, can have an interface file written called windowMgrName_makemenu This script/program reads the XML menu item in /usr/local/tce.menu/extensionName and converts to the native menu format of the target window manager. Then the window manager is restarted via windowMgrName_restart program.
All this happens seamlessly by way of these standardized calls from Tiny Core.
The interface program can be written in what ever language the extension maker is comfortable with. Just note that using a language not in the base implies that the window manager extension will need a .dep and thus increases it system resource demands.
I have written several example interface programs for flwm, jwm, and hackedbox, all using awk.