I would like to write my own FoE module. I checked out the source code from GitHub, installed the directory as a temporary extensions in FireFox which worked just fine. I then thought, if I would duplicate an existing module, add the new module name to js/internal.json and also change all names in the duplicated module source code to the new name, I should get an extra icon in the FoE toolbar, with identical function as the original module.
However, no extra icon was displayed on reloading the modified extension.
Please advise how to write a new module, or point me to a tutorial if it exists.
What I want to accomplish is an information page similar to this one: https://foebattlestats.herokuapp.com/battles/?comment=GEX%204-08