The lang prop on the <html> element must be a valid IETF's BCP 47 language tag.
This rule takes no arguments.
<html lang="en">
<html lang="en-US"><html>
<html lang="foo">The lang prop on the <html> element must be a valid IETF's BCP 47 language tag.
This rule takes no arguments.
<html lang="en">
<html lang="en-US"><html>
<html lang="foo">