The (Linux) location & filename given at http://gregorio-project.github.io/configuration-texworks.html is wrong. Per application hidden folders under the home directory have been deprecated for many years now.
You would expect the right file to be in ~/.config, e.g. ~/.config/TUG/TeXworks.conf, but in fact the files referred to are in ~/.local/share/TUG/TeXworks/configuration.