As a fellow Electron developer, I decided to snoop around in the Subform app and see if I could get it running on Ubuntu. Turns out it works fine, apart from a couple of cross-platform improvements.*
So, given all the other request (this forum filled up fast!) and your previous statements on gauging the interest, I wouldn't pay too much attention to this just yet, but an additional linux version should be easy to generate. Please have a look at how I do it for https://github.com/kilian/fromscratch which has a packaging script that builds windows, mac and linux artifacts in one go.
* I can help with that: https://blog.avocode.com/blog/4-must-know-tips-for-building-cross-platform-electron-apps
Here's some images to prove it: