In todays master, for example:

Warning: could not get message translation for "Create_blank_entry_linking_the_PDF" for locale en
Warning: could not get message translation for "Create_entry_based_on_XMP-metadata" for locale en
Warning: could not get message translation for "Create_entry_based_on_content" for locale en
Warning: could not get message translation for "Only_attach_PDF" for locale en

The problem is the old format using the underscore. I think the were missed, when @halirutan improved the language handling. Our tests should be adapted to report warnings in this cases (just report them as not found).