Name: UsernameCasePreserved.

Base Class: IdentifierClass.

Applicability: Usernames in security and application protocols.

Replaces: The SASLprep profile of Stringprep.

Width Mapping Rule: Map fullwidth and halfwidth code points to their decomposition mappings.

Additional Mapping Rule: None.

Case Mapping Rule: None.

Normalization Rule: NFC.

Directionality Rule: The "Bidi Rule" defined in RFC 5893 applies.

Enforcement: To be defined by security or application protocols that
use this profile.

Specification: RFC8265 Section 3.4.