Source: templates/content-message.php

<?php
/**
 * Content-message.php template file
 *
 * responsible for content on archive like pages. Only shows the message excerpt.
 *
 * For single message content please see single-message.php
 *
 * @author      Automattic
 * @package     Sensei
 * @category    Templates
 * @version     1.12.2
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}
?>

<article <?php post_class( array( 'post', 'sensei_message' ), get_the_ID() ); ?>>

	<section class="message-content">

		<?php
		/**
		 * Action that runs before the sensei {post_type} content.
		 * It runs inside the sensei content.php template.
		 * This applies to the specific post type that you've targeted.
		 *
		 * @since 1.9
		 *
		 * @hook sensei_content_message_before
		 *
		 * @param {int} $message_id The message ID.
		 *
		 * @hooked Sensei_Messages::the_message_title - 10
		 * @hooked Sensei_Messages::the_message_sender - 20
		 */
		do_action( 'sensei_content_message_before', get_the_ID() );
		?>

		<section class="entry">

			<?php
			/**
			 * Fires just before the post content in the content-message.php file.
			 *
			 * @since 1.9
			 *
			 * @hook sensei_content_message_inside_before
			 *
			 * @param {int} $message_id The message ID.
			 */
			do_action( 'sensei_content_message_inside_before', get_the_ID() );
			?>

			<p class="message-excerpt">

				<?php echo wp_kses_post( get_the_excerpt() ); ?>

			</p>

			<?php
			/**
			 * Fires just after the post content in the message-content.php file.
			 *
			 * @since 1.9
			 *
			 * @hook sensei_content_message_inside_after
			 *
			 * @param {int} $message_id The message ID.
			 */
			do_action( 'sensei_content_message_inside_after', get_the_ID() );
			?>

		</section> <!-- section .entry -->

		<?php
		/**
		 * This action runs after the sensei message content. It runs inside the sensei
		 * message-content.php template.
		 *
		 * @since 1.9
		 *
		 * @hook sensei_content_message_inside_after
		 *
		 * @param {int} $message_id The message ID.
		 */
		do_action( 'sensei_content_message_after', get_the_ID() );
		?>

	</section> <!-- article .message-content -->

</article> <!-- article .(<?php echo esc_attr( implode( ' ', get_post_class( array( 'sensei_message', 'post' ) ) ) ); ?>  -->