By altering the DTD file, you change the text displayed within the application.
You can find more information on how to [[mdchttps:Create_a_new_localization]] //developer.mozilla.org/en/Localization_Quick_Start_Guide on MDCMDN, ] along with [[mdc:Categoryhttps://developer.mozilla.org/en-US/docs/tag/Localization|other documentation]].