diff -r be944660c56a -r 3d72ae0968f4 wp/wp-includes/blocks/post-author.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/blocks/post-author.php	Tue Sep 27 16:37:53 2022 +0200
@@ -0,0 +1,60 @@
+<?php
+/**
+ * Server-side rendering of the `core/post-author` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/post-author` block on the server.
+ *
+ * @param  array    $attributes Block attributes.
+ * @param  string   $content    Block default content.
+ * @param  WP_Block $block      Block instance.
+ * @return string Returns the rendered author block.
+ */
+function render_block_core_post_author( $attributes, $content, $block ) {
+	if ( ! isset( $block->context['postId'] ) ) {
+		return '';
+	}
+
+	$author_id = get_post_field( 'post_author', $block->context['postId'] );
+	if ( empty( $author_id ) ) {
+		return '';
+	}
+
+	$avatar = ! empty( $attributes['avatarSize'] ) ? get_avatar(
+		$author_id,
+		$attributes['avatarSize']
+	) : null;
+
+	$byline  = ! empty( $attributes['byline'] ) ? $attributes['byline'] : false;
+	$classes = array_merge(
+		isset( $attributes['itemsJustification'] ) ? array( 'items-justified-' . $attributes['itemsJustification'] ) : array(),
+		isset( $attributes['textAlign'] ) ? array( 'has-text-align-' . $attributes['textAlign'] ) : array()
+	);
+
+	$wrapper_attributes = get_block_wrapper_attributes( array( 'class' => implode( ' ', $classes ) ) );
+
+	return sprintf( '<div %1$s>', $wrapper_attributes ) .
+	( ! empty( $attributes['showAvatar'] ) ? '<div class="wp-block-post-author__avatar">' . $avatar . '</div>' : '' ) .
+	'<div class="wp-block-post-author__content">' .
+	( ! empty( $byline ) ? '<p class="wp-block-post-author__byline">' . wp_kses_post( $byline ) . '</p>' : '' ) .
+	'<p class="wp-block-post-author__name">' . get_the_author_meta( 'display_name', $author_id ) . '</p>' .
+	( ! empty( $attributes['showBio'] ) ? '<p class="wp-block-post-author__bio">' . get_the_author_meta( 'user_description', $author_id ) . '</p>' : '' ) .
+	'</div>' .
+	'</div>';
+}
+
+/**
+ * Registers the `core/post-author` block on the server.
+ */
+function register_block_core_post_author() {
+	register_block_type_from_metadata(
+		__DIR__ . '/post-author',
+		array(
+			'render_callback' => 'render_block_core_post_author',
+		)
+	);
+}
+add_action( 'init', 'register_block_core_post_author' );