You can hit save after editing and it will put it will be where its supposed to go itself.
If you want to edit the config with another app - it should be under:
- win - %appdata%\Godot\app_userdata\TEXTREME
- mac - ~/Library/Application Support/Godot/app_userdata/TEXTREME
- linux - ~/.local/share/godot/app_userdata/TEXTREME
config files for Textreme 2 are stored in a similar place, just replace `TEXTREME` with `Textreme2`