wp-includes/l10n.php:1865Restores the translations according to the previous locale.
string|falsefunction restore_previous_locale() { /* @var WP_Locale_Switcher $wp_locale_switcher */ global $wp_locale_switcher; if ( ! $wp_locale_switcher ) { return false; } return $wp_locale_switcher->restore_previous_locale();}Introduced in 4.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/l10n.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.