This bug is a warning, not a fatal error: “The translator cannot reorder the arguments.”  Depending on the language, it may be a real pain.

“Basically, we should use the name of an Action or ArgumentParser attribute whenever it makes sense. Hopefully that will make it more intuitive what these mean when people are translating them.”  Exactly.  That’s why I suggested %(program_name) instead of %(prog); keep in mind translators are not necessarily programmers, so the familiar argparse terms may not make sense to them.

If Georg is okay with the lack of tests (apart manual testing showing that xgettext does not print warnings anymore), I will apply your changes and commit this tonight, which should be in time for beta1.