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Table of Contents
Quick Take
Match registered tags without regard to letter case
Explain a language tag containing two region subtags
Explain an extended language subtag with the wrong prefix
Validate an extended language subtag after its registered prefix
Validate multiple uniquely prefixed extensions
Accept an IANA-grandfathered language tag
Validate a private-use language tag
Explain why a repeated variant is invalid
Validate language, script, region, and variant subtags together
Explain an extension singleton without extension content
Various examples