WordPress at a glance
function is not described

post_excerpt_meta_box() WP 2.6.0

Display post excerpt form fields.

No Hooks.

Return

Nothing (null).

Usage

post_excerpt_meta_box( $post );
$post(object) (required)

Code of post excerpt meta box: wp-admin/includes/meta-boxes.php VER 5.0.3

<?php
function post_excerpt_meta_box($post) {
?>
<label class="screen-reader-text" for="excerpt"><?php _e('Excerpt') ?></label><textarea rows="1" cols="40" name="excerpt" id="excerpt"><?php echo $post->post_excerpt; // textarea_escaped ?></textarea>
<p><?php
	printf(
		/* translators: %s: Codex URL */
		__( 'Excerpts are optional hand-crafted summaries of your content that can be used in your theme. <a href="%s">Learn more about manual excerpts</a>.' ),
		__( 'https://codex.wordpress.org/Excerpt' )
	);
?></p>
<?php
}