Tweny Twenty Child theme | Add Subtitle to entry-header.php

entry-header.php

<?php
/**
 * Displays the post header
 *
 * @package WordPress
 * @subpackage Twenty_Twenty
 * @since Twenty Twenty 1.0
 */

$entry_header_classes = '';

if ( is_singular() ) {
	$entry_header_classes .= ' header-footer-group';
}

?>

<header class="entry-header has-text-align-center<?php echo esc_attr( $entry_header_classes ); ?>">

	<div class="entry-header-inner section-inner medium">

		<?php
			/**
			 * Allow child themes and plugins to filter the display of the categories in the entry header.
			 *
			 * @since Twenty Twenty 1.0
			 *
			 * @param bool   Whether to show the categories in header, Default true.
			 */
		$show_categories = apply_filters( 'twentytwenty_show_categories_in_entry_header', true );

		if ( true === $show_categories && has_category() ) {
			?>

			<div class="entry-categories">
				<span class="screen-reader-text"><?php _e( 'Categories', 'twentytwenty' ); ?></span>
				<div class="entry-categories-inner">
					<?php the_category( ' ' ); ?>
				</div><!-- .entry-categories-inner -->
			</div><!-- .entry-categories -->

			<?php
		}

		if ( is_singular() ) {
			the_title( '<h1 class="entry-title">', '</h1>' );
			if( function_exists( 'the_subtitle' ) ) { the_subtitle( '<h2 class="subtitle">', '</h2>' ); }
		} else {
			the_title( '<h2 class="entry-title heading-size-1"><a href="' . esc_url( get_permalink() ) . '">', '</a></h2>' );
			if( function_exists( 'the_subtitle' ) ) { the_subtitle( '<h3 class="subtitle">', '</h3>' ); }
		}

		$intro_text_width = '';

		if ( is_singular() ) {
			$intro_text_width = ' small';
		} else {
			$intro_text_width = ' thin';
		}

		if ( has_excerpt() && is_singular() ) {
			?>

			<div class="intro-text section-inner max-percentage<?php echo $intro_text_width; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- static output ?>">
				<?php the_excerpt(); ?>
			</div>

			<?php
		}

		// Default to displaying the post meta.
		twentytwenty_the_post_meta( get_the_ID(), 'single-top' );
		?>

	</div><!-- .entry-header-inner -->

</header><!-- .entry-header -->