irregular top-level constant
As defined in RFC5646
Implementation
const irregular = [
'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',
];