Fonte per "Barma Cotze"? Di certo non fa parte della toponomastica ufficiale: https://www.regione.vda.it/enti_locali/documento_i.asp?pk_documenti=1215

No, penso che sia opportuno utilizzare tag:name. tag:official_name è solo per i nomi ufficiali ma meno diffusi (esempio: Repubblica Italiana sarebbe tag:official_name, invece Italia sarebbe tag:name). Per Hérin questa distinzione non esiste perché Herin senza l'accento non è presente da nessuna parte: sul sito del turismo, per esempio, appare Hérin con l'accento.

Hérin si scrive con l'accento, per legge. Potresti cortesemente correggere tutti gli Hérin sbagliati che hai aggiunto? https://www.regione.vda.it/amministrazione/leggi/bollettino_ufficiale_new/archive/2022/61-2022.pdf#page=31

Should have fixed all of them. Let me know if you spot anything out of the ordinary. Thanks!

Hi ivanbranco, thanks! Will correct ASAP.

Unlike the official toponymy approved by regional decree, which went through a peer-review of a toponymy committee, of the municipal council and of the autonomous region, there is no guarantee that the same happened to those two documents. I suppose it could be an alt_name or old_name candidate, since we don't know if that was the name previously used prior to the adoption of 11 december 2012 regional decree n. 464., but it is possible it is simply a mistake that keeps on perpetuating itself. And as the municipality of Sarre itself reminds the reader on its website:
https://www.comune.sarre.ao.it/il-paese-e-le-associazioni/paese/frazioni/
"Lein".

Now, I do have to thank you for mentioning the alt_name_1 tag, which I have used for Champdepraz, where the regional decree mentions both the official name and alternative names: https://www.regione.vda.it/enti_locali/documento_i.asp?pk_documenti=1181

But in the case of the municipality of Sarre, no alternative names were provided. Therefore, I cannot recommend Leyn as an alt_name or old_name.

Following your comments I will, however, review previous edits of mine to make sure that when a municipality has established "alternative/in-use names", that they are reflected in the tags of the locality/hamlet/village too. Of course, those cannot supersede the official name, by definition.

Does this answer your concern with respect to this particular village?

{{reply to|ivanbranco}} Hi Ivan,

The official names of localities, hamlets and villages in Valle d'Aosta / Vallée d'Aoste are determined by the municipalities in consultation with and sent to the president of the autonomous region for approval, which is usually done by regional decree. Not all municipalities of Aosta Valley have done this, but most have. You can consult a full list of official toponyms here: https://www.regione.vda.it/enti_locali/cartella_i.asp?pk_cartelle=183

As it turns out, many toponyms are simply incorrect on digital cartography websites such as OpenStreetMap, Google Maps and Apple Maps (in ascending order of errors). As for alternative, local or old names, they may be added using alt_name I suppose, but I have solely relied on official toponyms approved by law for my edits. Happy to discuss specific toponyms if you have specific questions about each of them.