How to add custom language layout inside Gboard (Google Keyboard), created by me

The problem is that I want to use a modified layout for Google Keyboard and use it inside the Gboard app (because of its features). I don't want to: * create [separate own InputMethod](https://code.tutsplus.com/tutorials/create-a-custom-keyboard-on-android--cms-22615) * use another app (Hacker's Keyboard or SwiftKey) Does anyone know how to edit Gboard .xml files, maybe? Or do it officially through a plugin or some code? PS. I can code.