WordPress at a glance
function is not described

wp_dashboard_site_activity() WP 3.8.0

Callback function for Activity widget.

No Hooks.

Return

Nothing (null).

Usage

wp_dashboard_site_activity();

Code of wp dashboard site activity: wp-admin/includes/dashboard.php WP 5.2.2

<?php
function wp_dashboard_site_activity() {

	echo '<div id="activity-widget">';

	$future_posts = wp_dashboard_recent_posts(
		array(
			'max'    => 5,
			'status' => 'future',
			'order'  => 'ASC',
			'title'  => __( 'Publishing Soon' ),
			'id'     => 'future-posts',
		)
	);
	$recent_posts = wp_dashboard_recent_posts(
		array(
			'max'    => 5,
			'status' => 'publish',
			'order'  => 'DESC',
			'title'  => __( 'Recently Published' ),
			'id'     => 'published-posts',
		)
	);

	$recent_comments = wp_dashboard_recent_comments();

	if ( ! $future_posts && ! $recent_posts && ! $recent_comments ) {
		echo '<div class="no-activity">';
		echo '<p class="smiley" aria-hidden="true"></p>';
		echo '<p>' . __( 'No activity yet!' ) . '</p>';
		echo '</div>';
	}

	echo '</div>';
}