Source

File: wp-includes/l10n.php

function unload_textdomain( $domain ) {
	global $l10n, $l10n_unloaded;

	$l10n_unloaded = (array) $l10n_unloaded;

	/**
	 * Filters whether to override the text domain unloading.
	 *
	 * @since 3.0.0
	 *
	 * @param bool   $override Whether to override the text domain unloading. Default false.
	 * @param string $domain   Text domain. Unique identifier for retrieving translated strings.
	 */
	$plugin_override = apply_filters( 'override_unload_textdomain', false, $domain );

	if ( $plugin_override ) {
		$l10n_unloaded[ $domain ] = true;

		return true;
	}

	/**
	 * Fires before the text domain is unloaded.
	 *
	 * @since 3.0.0
	 *
	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
	 */
	do_action( 'unload_textdomain', $domain );

	if ( isset( $l10n[ $domain ] ) ) {
		unset( $l10n[ $domain ] );

		$l10n_unloaded[ $domain ] = true;

		return true;
	}

	return false;
}