It seems the Bitmap Fonts.js plugin uses nwjs functions extensively (filesystem access), I don't know javascript enough to convert it to a hardcoded list and web requests.
For some reason replacing the bitmap loading functions with a NO-OP yesterday only broke text on the menu (didn't try after that) but with your file it gets stuck on the loading screen without making any other requests, I don't even understand how this can be related… The only messages in the console are about pixi.js and I think it did print them with the NO-OP.
Ah, I’m really sorry about that. Since MV keeps the source code for everything easily available and I haven’t worked with it in a long time now I forgot that plugins used in RPG Maker games may not be public or free, so I just modified it to work on the web for the Escaped Chasm web version (the second link in my previous post was supposed to link there). I have deleted it from there now.