handle and utilize Claims using language tags.

Condition: when receiving language-tagged Claims such as localized middle_name variants

It is also RECOMMENDED that Clients be written in a manner that they can handle and utilize Claims using language tags.

interpret supplied language tag values case-insensitively.

Condition: when processing language-tagged Claim Names such as localized middle_name variants

However, since BCP47 language tag values are case insensitive, implementations SHOULD interpret the language tag values supplied in a case-insensitive manner.

return an error solely because some or all requested Claim locales are unsupported by the OpenID Provider.

Condition: when claims_locales requests apply to returned Claims such as middle_name

An error SHOULD NOT result if some or all of the requested locales are not supported by the OpenID Provider.

make language tag values for Claims only as specific as necessary.

Condition: when using language-tagged middle_name Claim Names

Per the recommendations in BCP47, language tag values for Claims SHOULD only be as specific as necessary.

spell language tag values used in Claim Names using the character case with which they are registered in the IANA Language Subtag Registry.

Condition: when using language-tagged middle_name Claim Names

Since Claim Names are case sensitive, it is strongly RECOMMENDED that language tag values used in Claim Names be spelled using the character case with which they are registered in the IANA "Language Subtag Registry" IANA.Language.

represent the middle_name Claim Value in multiple languages and scripts when using language-tagged Claim Names.

Condition: when middle_name is treated as a human-readable Claim Value

Human-readable Claim Values and Claim Values that reference human-readable values MAY be represented in multiple languages and scripts.

treat the profile scope value as optional; when used, it requests access to default profile Claims including middle_name.

Condition: when requesting Claims using OpenID Connect scope values

OPTIONAL. This scope value requests access to the End-User's default profile Claims, which are: name, family_name, given_name, middle_name, nickname, preferred_username, profile, picture, website, gender, birthdate, zoneinfo, locale, and updated_at.

try to match requested Claim locales with Claims the OP has.

Condition: when returning localized Claim Values such as localized middle_name variants

Where possible, OPs SHOULD try to match requested Claim locales with Claims it has.

return Claims without language tags when using the single language and script requested or otherwise determined.

Condition: when the OP determines that the End-User and Client are requesting Claims in only one set of languages and scripts

When the OP determines, either through the claims_locales parameter, or by other means, that the End-User and Client are requesting Claims in only one set of languages and scripts, it is RECOMMENDED that OPs return Claims without language tags when they employ this language and script.