From catalog/rfc5646-langtag.abnf rule: region

Definition

region = 2ALPHA / 3DIGIT

    

Info

Rulename
region
Dependencies
ALPHA, DIGIT, region
Used Builtins
ALPHA, DIGIT

Alphabet

Translations

Railroad Diagram

region ALPHA ALPHA DIGIT DIGIT DIGIT

Swift Regular Expression

[A-Za-z][A-Za-z]|[0-9][0-9][0-9]

POSIX Extended Regular Expression

[A-Za-z][A-Za-z]|[0-9][0-9][0-9]