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function wp_send_note_notification( WP_User $user, WP_Comment $comment, ?WP_Post $post ): bool {
	$switched_locale = switch_to_user_locale( $user->ID );

	/*
	 * The site title and the post title are escaped on the way into the database,
	 * and note content is stored as HTML. Both are reversed once here for the
	 * plain text arena of emails. Decoding a second time would go too far and
	 * resolve entities the author meant to be read literally.
	 */
	$blogname    = wp_specialchars_decode( get_bloginfo( 'name', 'display' ), ENT_QUOTES );
	$post_title  = $post ? wp_specialchars_decode( get_the_title( $post ), ENT_QUOTES ) : '';
	$author_name = $comment->comment_author ? $comment->comment_author : __( 'Someone' );
	$content     = wp_specialchars_decode( wp_strip_all_tags( $comment->comment_content ) );

	/*
	 * The rest of the message is composed for the recipient, and so is the editor
	 * link: get_edit_post_link() answers for whoever is current, which here is the
	 * note's author over REST and nobody at all under WP-Cron.
	 */
	$edit_link = '';
	if ( $post ) {
		$previous_user_id = get_current_user_id();
		wp_set_current_user( $user->ID );
		$edit_link = (string) get_edit_post_link( $post->ID, 'url' );
		wp_set_current_user( $previous_user_id );
	}

	/* translators: 1: Note author's name, 2: Post title. */
	$message = sprintf( __( '%1$s mentioned you in a note on "%2$s".' ), $author_name, $post_title );
	/* translators: Note mention notification email subject. 1: Site title, 2: Post title. */
	$subject = sprintf( __( '[%1$s] You were mentioned in a note on "%2$s"' ), $blogname, $post_title );

	$lines = array( $message, '' );
	if ( '' !== $content ) {
		$lines[] = $content;
	}
	if ( $edit_link ) {
		$lines[] = '';
		$lines[] = __( 'Edit This' ) . ': ' . $edit_link;
	}

	// Declared explicitly so a filtered default cannot turn the message into HTML.
	$headers = 'Content-Type: text/plain; charset="' . get_option( 'blog_charset' ) . '"';

	$sent = wp_mail( $user->user_email, $subject, implode( "\n", $lines ), $headers );

	if ( $switched_locale ) {
		restore_previous_locale();
	}

	return $sent;
}