faq_graph_schema.php

<?php
/**
 * Render the schema graph for the acf/gb-faq block.
 *
 * @param array                 $graph   Schema data for the current page.
 * @param WP_Block_Parser_Block $block   The block data array.
 * @param Meta_Tags_Context     $context A value object with context variables.
 *
 * @return array Our Schema graph.
 */
public function faq_schema( $graph, $block, $context ) {
  // Format the block data into the expected format from acf.
  $acf_block = acf_prepare_block( $block['attrs'] );

  // Setup postdata allowing get_field() to work.
  acf_setup_meta( $acf_block['data'], $acf_block['id'], true );

  // Find the index of the WebPage Item and add the FAQPage item if necessary.
  foreach ( $graph as $index => $graph_piece ) {
    if ( isset( $graph_piece['@type'] ) ) {
      if ( is_array( $graph_piece['@type'] ) && in_array( 'WebPage', $graph_piece['@type'], true ) ) {
        $faqi                      = $index;
        $graph[ $faqi ]['@type'][] = 'FAQPage';
        $graph[ $faqi ]['@type']   = array_unique( $graph[ $faqi ]['@type'] );
      } elseif ( is_string( $graph_piece['@type'] ) && $graph_piece['@type'] === 'WebPage' ) {
        $faqi                    = $index;
        $graph[ $faqi ]['@type'] = array(
          'WebPage',
          'FAQPage',
        );
      }
    }
  }

  $graph_questions = array();
  // Loop over the questions in the block content.
  foreach ( get_field( 'content' ) as $si => $section ) {
    if ( $section['acf_fc_layout'] ) {
      $section_id = 'section-' . $si . '-' . $acf_block['id'];
      foreach ( $section['questions'] as $qi => $q ) {
        $question_id = 'question-' . $qi . '-' . $section_id;

        // Format the question as per Schema.org spec. But yeah, let's be real
        // here, I just looked at how yoast strucures it in their internal FAQ
        // block.
        $graph_questions[] = array(
          '@type'          => 'Question',
          '@id'            => get_permalink() . '#' . $question_id,
          'url'            => get_permalink() . '#' . $question_id,
          'name'           => $q['question'],
          'answerCount'    => 1,
          'acceptedAnswer' => array(
            '@type'      => 'Answer',
            'text'       => $q['answer'],
            'inLanguage' => get_locale(),
          ),
          'inLanguage'     => get_locale(),
        );

        // If we do not yet have a mainEntity, create it.
        if ( ! isset( $graph[ $faqi ]['mainEntity'] ) || ! is_array( $graph[ $faqi ]['mainEntity'] ) ) {
          $graph[ $faqi ]['mainEntity'] = array();
        }

        // Hook the question @id into the mainEntity array.
        $graph[ $faqi ]['mainEntity'][] = array(
          '@id' => get_permalink() . '#' . $question_id,
        );
      }
    }
  }

  // Reset postdata.
  acf_reset_meta( $acf_block['id'] );

  // Merge our questions into the main graph array and return.
  return array_merge( $graph, $graph_questions );
}
add_action( 'wpseo_schema_block_acf/gb-faq', 'faq_schema', 10, 3 );

Can you add an opening <?php - then you get syntax highlighting and people could install the gist via Github Updater directly to their sites.