TY for your answer. For now, I use *sdiff* to edit and merge with new *.pacnew* files. I was confused this time because Thunar explorer show me local.gen as a binary! But this is not the case, so I will merge the two local.gen.
Have a closer look to the filename: there is "locale.gen", the plain text file where you uncomment the entries you need. And there is "locale_gen" , really a binary, which you execute after editing the locale.gen.
Best regards, Nelson.