language_tags::GRANDFATHERED_IRREGULAR

pub const GRANDFATHERED_IRREGULAR: [&'static str; 17] = ["en-GB-oed", "i-ami", "i-bnn", "i-default", "i-enochian", "i-hak",
 "i-klingon", "i-lux", "i-mingo", "i-navajo", "i-pwn", "i-tao", "i-tay",
 "i-tsu", "sgn-BE-FR", "sgn-BE-NL", "sgn-CH-DE"]

Contains the 17 irregular old language tags not matching the standard grammer of tags.