Some users of our application are asking to increase the font size.
In Tryton4 + GTK2 we used the file \etc\gtk-2.0\gtkrc for this purpose.
In Tryton5 + GTK3 we have tried to use the file \etc\gtk-3.0\settings.ini:
There was no settings.ini file in these places, so we had to create it ourselves.
We tried all these options to place the file settings.ini, but the font did not change.
The problem was solved this way.
We created the following file: ~\.config\tryton\5.2\theme.css