Source
File: wp-includes/widgets/class-wp-widget-media-gallery.php
public function __construct() {
parent::__construct(
'media_gallery',
__( 'Gallery' ),
array(
'description' => __( 'Displays an image gallery.' ),
'mime_type' => 'image',
)
);
$this->l10n = array_merge(
$this->l10n,
array(
'no_media_selected' => __( 'No images selected' ),
'add_media' => _x( 'Add Images', 'label for button in the gallery widget; should not be longer than ~13 characters long' ),
'replace_media' => '',
'edit_media' => _x( 'Edit Gallery', 'label for button in the gallery widget; should not be longer than ~13 characters long' ),
)
);
}