I do not have an official transliteration but a better question could be: Is it legally okay to use unaccented letters of Romanized languages like French, double letters like the Nordic "ae"; or is there a different legal condition for each country?
Feb 16, 2021, 21:59 by eliz@gnu.org:

>> Date: Tue, 16 Feb 2021 19:55:13 +0100 (CET)
>> Cc: Emacs Devel <emacs-devel@gnu.org>
>> From: xenodasein--- via "Emacs development discussions." <emacs-devel@gnu.org>
>> > Please use your full legal name (in ASCII characters) as the subject
>> > line of the message.
>> Hello Lars,
>> What is the process for citizens of countries with non-ASCII legal names?
>>
>
> Can you transliterate the name in ASCII characters?
> If not, we will need to ask the copyright clerk for instructions in
> this case.
>
> Thanks.
>