Source

File: wp-admin/includes/class-language-pack-upgrader-skin.php

public function before() {
		$name = $this->upgrader->get_name_for_update( $this->language_update );

		echo '<div class="update-messages lp-show-latest">';

		/* translators: 1: Project name (plugin, theme, or WordPress), 2: Language. */
		printf( '<h2>' . __( 'Updating translations for %1$s (%2$s)&#8230;' ) . '</h2>', $name, $this->language_update->language );
	}