The name of the protocol in a form suitable for display to users, such as "AIM" or "Yahoo!", or a string based on
protocol_name (currently constructed by putting the first
character in title case, but this is not guaranteed) if no better name is available or the TP_PROTOCOL_FEATURE_CORE feature
has not been prepared.
This is effectively in the C locale (international English); user interfaces requiring a localized protocol name should look one up in their own message catalog based on either protocol_name or english_name, but should use this English version as a fallback if no translated version can be found.