The default value for /schemas/apps/gedit-2/preferences/encodings/auto_detected
has to following comment:

<!-- Translators: This is the sorted list of encodings used by gedit
        for auto-detecting the encoding of a file. You may want to customize it adding
        encodings that are common in your country, for instance the GB18030 encoding
        for the Chinese translation. You may also want to remove the ISO-8859-15 encoding
        (covering English and most Western European languages) if you think people
        in you country will rarely use it.
        "CURRENT" is a magic value used by gedit and it represents the encoding
        for the current locale, so please don't translate the "CURRENT" term.
        Only recognized encodings are used.
        See http://svn.gnome.org/viewcvs/gedit/trunk/gedit/gedit-encodings.c?view=markup for
        a list of supported encodings -->[UTF-8,CURRENT,ISO-8859-15,UTF-16]

The dz translation doesn't seem to be a list of encoding names:

<default>[ཡུ་ཊི་ཨེཕ་-༨  ད་ལྟོ་  ཨའི་ཨེསི་ཨོ་-༨༨༥༩-༡༥  ཡུ་ཊི་ཨེཕ་-༡༦]</default>