The description parameter in g_application_add_main_option() can’t be NULL.
Passing NULL would be useful for showing that the added command option does
not have a description. g_application_add_main_option_entries() does not seem
to require descriptions of the command options.
Why does it matter? It’s possible to pass an empty string.
See Command line option without a description breaks translation (#124) · Issues · GNOME / glibmm · GitLab.