diff -r 3d4e9c994f10 -r a86126ab1dd4 wp/wp-admin/includes/export.php
--- a/wp/wp-admin/includes/export.php	Tue Oct 22 16:11:46 2019 +0200
+++ b/wp/wp-admin/includes/export.php	Tue Dec 15 13:49:49 2020 +0100
@@ -25,7 +25,7 @@
  * @since 2.1.0
  *
  * @global wpdb    $wpdb WordPress database abstraction object.
- * @global WP_Post $post Global `$post`.
+ * @global WP_Post $post Global post object.
  *
  * @param array $args {
  *     Optional. Arguments for generating the WXR export file for download. Default empty array.
@@ -79,7 +79,7 @@
 	if ( ! empty( $sitename ) ) {
 		$sitename .= '.';
 	}
-	$date        = date( 'Y-m-d' );
+	$date        = gmdate( 'Y-m-d' );
 	$wp_filename = $sitename . 'WordPress.' . $date . '.xml';
 	/**
 	 * Filters the export filename.
@@ -96,7 +96,7 @@
 	header( 'Content-Disposition: attachment; filename=' . $filename );
 	header( 'Content-Type: text/xml; charset=' . get_option( 'blog_charset' ), true );
 
-	if ( 'all' != $args['content'] && post_type_exists( $args['content'] ) ) {
+	if ( 'all' !== $args['content'] && post_type_exists( $args['content'] ) ) {
 		$ptype = get_post_type_object( $args['content'] );
 		if ( ! $ptype->can_export ) {
 			$args['content'] = 'post';
@@ -106,34 +106,37 @@
 	} else {
 		$post_types = get_post_types( array( 'can_export' => true ) );
 		$esses      = array_fill( 0, count( $post_types ), '%s' );
-		$where      = $wpdb->prepare( "{$wpdb->posts}.post_type IN (" . implode( ',', $esses ) . ')', $post_types );
+
+		// phpcs:ignore WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare
+		$where = $wpdb->prepare( "{$wpdb->posts}.post_type IN (" . implode( ',', $esses ) . ')', $post_types );
 	}
 
-	if ( $args['status'] && ( 'post' == $args['content'] || 'page' == $args['content'] ) ) {
+	if ( $args['status'] && ( 'post' === $args['content'] || 'page' === $args['content'] ) ) {
 		$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_status = %s", $args['status'] );
 	} else {
 		$where .= " AND {$wpdb->posts}.post_status != 'auto-draft'";
 	}
 
 	$join = '';
-	if ( $args['category'] && 'post' == $args['content'] ) {
-		if ( $term = term_exists( $args['category'], 'category' ) ) {
+	if ( $args['category'] && 'post' === $args['content'] ) {
+		$term = term_exists( $args['category'], 'category' );
+		if ( $term ) {
 			$join   = "INNER JOIN {$wpdb->term_relationships} ON ({$wpdb->posts}.ID = {$wpdb->term_relationships}.object_id)";
 			$where .= $wpdb->prepare( " AND {$wpdb->term_relationships}.term_taxonomy_id = %d", $term['term_taxonomy_id'] );
 		}
 	}
 
-	if ( 'post' == $args['content'] || 'page' == $args['content'] || 'attachment' == $args['content'] ) {
+	if ( in_array( $args['content'], array( 'post', 'page', 'attachment' ), true ) ) {
 		if ( $args['author'] ) {
 			$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_author = %d", $args['author'] );
 		}
 
 		if ( $args['start_date'] ) {
-			$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_date >= %s", date( 'Y-m-d', strtotime( $args['start_date'] ) ) );
+			$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_date >= %s", gmdate( 'Y-m-d', strtotime( $args['start_date'] ) ) );
 		}
 
 		if ( $args['end_date'] ) {
-			$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_date < %s", date( 'Y-m-d', strtotime( '+1 month', strtotime( $args['end_date'] ) ) ) );
+			$where .= $wpdb->prepare( " AND {$wpdb->posts}.post_date < %s", gmdate( 'Y-m-d', strtotime( '+1 month', strtotime( $args['end_date'] ) ) ) );
 		}
 	}
 
@@ -144,21 +147,28 @@
 	 * Get the requested terms ready, empty unless posts filtered by category
 	 * or all content.
 	 */
-	$cats = $tags = $terms = array();
+	$cats  = array();
+	$tags  = array();
+	$terms = array();
 	if ( isset( $term ) && $term ) {
 		$cat  = get_term( $term['term_id'], 'category' );
 		$cats = array( $cat->term_id => $cat );
 		unset( $term, $cat );
-	} elseif ( 'all' == $args['content'] ) {
+	} elseif ( 'all' === $args['content'] ) {
 		$categories = (array) get_categories( array( 'get' => 'all' ) );
 		$tags       = (array) get_tags( array( 'get' => 'all' ) );
 
 		$custom_taxonomies = get_taxonomies( array( '_builtin' => false ) );
-		$custom_terms      = (array) get_terms( $custom_taxonomies, array( 'get' => 'all' ) );
+		$custom_terms      = (array) get_terms(
+			array(
+				'taxonomy' => $custom_taxonomies,
+				'get'      => 'all',
+			)
+		);
 
 		// Put categories in order with no child going before its parent.
 		while ( $cat = array_shift( $categories ) ) {
-			if ( $cat->parent == 0 || isset( $cats[ $cat->parent ] ) ) {
+			if ( 0 == $cat->parent || isset( $cats[ $cat->parent ] ) ) {
 				$cats[ $cat->term_id ] = $cat;
 			} else {
 				$categories[] = $cat;
@@ -167,7 +177,7 @@
 
 		// Put terms in order with no child going before its parent.
 		while ( $t = array_shift( $custom_terms ) ) {
-			if ( $t->parent == 0 || isset( $terms[ $t->parent ] ) ) {
+			if ( 0 == $t->parent || isset( $terms[ $t->parent ] ) ) {
 				$terms[ $t->term_id ] = $t;
 			} else {
 				$custom_terms[] = $t;
@@ -318,7 +328,7 @@
 			/**
 			 * Filters whether to selectively skip term meta used for WXR exports.
 			 *
-			 * Returning a truthy value to the filter will skip the current meta
+			 * Returning a truthy value from the filter will skip the current meta
 			 * object from being exported.
 			 *
 			 * @since 4.6.0
@@ -418,7 +428,7 @@
 	 * @return bool
 	 */
 	function wxr_filter_postmeta( $return_me, $meta_key ) {
-		if ( '_edit_lock' == $meta_key ) {
+		if ( '_edit_lock' === $meta_key ) {
 			$return_me = true;
 		}
 		return $return_me;
@@ -458,7 +468,7 @@
 	<title><?php bloginfo_rss( 'name' ); ?></title>
 	<link><?php bloginfo_rss( 'url' ); ?></link>
 	<description><?php bloginfo_rss( 'description' ); ?></description>
-	<pubDate><?php echo date( 'D, d M Y H:i:s +0000' ); ?></pubDate>
+	<pubDate><?php echo gmdate( 'D, d M Y H:i:s +0000' ); ?></pubDate>
 	<language><?php bloginfo_rss( 'language' ); ?></language>
 	<wp:wxr_version><?php echo WXR_VERSION; ?></wp:wxr_version>
 	<wp:base_site_url><?php echo wxr_site_url(); ?></wp:base_site_url>
@@ -491,7 +501,7 @@
 	<?php endforeach; ?>
 	<?php foreach ( $terms as $t ) : ?>
 	<wp:term>
-		<wp:term_id><?php echo wxr_cdata( $t->term_id ); ?></wp:term_id>
+		<wp:term_id><?php echo intval( $t->term_id ); ?></wp:term_id>
 		<wp:term_taxonomy><?php echo wxr_cdata( $t->taxonomy ); ?></wp:term_taxonomy>
 		<wp:term_slug><?php echo wxr_cdata( $t->slug ); ?></wp:term_slug>
 		<wp:term_parent><?php echo wxr_cdata( $t->parent ? $terms[ $t->parent ]->slug : '' ); ?></wp:term_parent>
@@ -503,7 +513,7 @@
 	</wp:term>
 	<?php endforeach; ?>
 	<?php
-	if ( 'all' == $args['content'] ) {
+	if ( 'all' === $args['content'] ) {
 		wxr_nav_menu_terms();}
 	?>
 
@@ -515,7 +525,7 @@
 	<?php
 	if ( $post_ids ) {
 		/**
-		 * @global WP_Query $wp_query
+		 * @global WP_Query $wp_query WordPress Query object.
 		 */
 		global $wp_query;
 
@@ -575,7 +585,7 @@
 		<wp:post_type><?php echo wxr_cdata( $post->post_type ); ?></wp:post_type>
 		<wp:post_password><?php echo wxr_cdata( $post->post_password ); ?></wp:post_password>
 		<wp:is_sticky><?php echo intval( $is_sticky ); ?></wp:is_sticky>
-				<?php	if ( $post->post_type == 'attachment' ) : ?>
+				<?php	if ( 'attachment' === $post->post_type ) : ?>
 		<wp:attachment_url><?php echo wxr_cdata( wp_get_attachment_url( $post->ID ) ); ?></wp:attachment_url>
 	<?php endif; ?>
 				<?php wxr_post_taxonomy(); ?>
@@ -585,7 +595,7 @@
 					/**
 					 * Filters whether to selectively skip post meta used for WXR exports.
 					 *
-					 * Returning a truthy value to the filter will skip the current meta
+					 * Returning a truthy value from the filter will skip the current meta
 					 * object from being exported.
 					 *
 					 * @since 3.3.0
@@ -628,7 +638,7 @@
 						/**
 						 * Filters whether to selectively skip comment meta used for WXR exports.
 						 *
-						 * Returning a truthy value to the filter will skip the current meta
+						 * Returning a truthy value from the filter will skip the current meta
 						 * object from being exported.
 						 *
 						 * @since 4.0.0