That step can be completely skipped for languages that can only be displayed with the graphical frontend of Debian Installer

The language coordinator must provide a file containing all characters needed for properly displaying the language, not including characters which are part of the ASCII character set (characters in the 32-127 range). This file will be used by the font reduction mechanism (the UTF-8 font used in Debian Installer is reduced for size constraints) and is needed for all Latin languages and all non-Latin languages with reasonably sized alphabet.

It is allowed to add characters that can be entered directly using a "standard" keyboard for the language and are printed on the tops of keys, for example as displayed on http://en.wikipedia.org/wiki/Keymap. This includes characters accessible through alt-gr and characters that can be created using dead keys.

This step is optional for languages that can only be rendered with the graphical version of Debian Installer (languages in category 4 at the previous step). For languages which must used the graphical version of Debian Installer, this step is automatically considered completed. Translators can however still provide the required file which could be useful in the future.

Below is an example of the contents of this file for a Latin language, namely French:

àâéèëêïîôùûüÿÀÂÉÈËÊÔÙÛÜŸÇ°£§µ

For this step to be completed, the new file must have been committed in the installer/built/needed-characters directory. The file name must be the ISO-639 language code with .utf as extension.

As long as the language remains a prospective language, that file should be named after the language's ISO code and the .prospective file extension. The extension will be changed to .utf when the language is completely supported.

The Debian Installer i18n coordinators will record this information in the supported languages list by changing the nlp_step field value to needed_characters.