- The current code forces the greeter to be run with the "sddm", without any
  possibility to configure it. It would be better if this is configurable as we
  don't want to pollute the usernames space. (it seems like it the _sddm name
  would be more in the current best practices)

- The current pam code tries to detect the prompts with regular expressions
  instead of using the prompt as is. To do so, it forces the helper
  environment to LANG=C. It would be better to drop that logic and just use
  the pam prompt.