world-game/site/templates/expertise.json.php

<?php

$specificData = [
  'pageTitle' => $page->writer()->value(),
  'items'     => $page->body()->toBlocks()->filter(fn($b) => $b->type() === 'text')->map(fn($block) => [
    'text' => $block->text()->value()
  ])->values()
];

$pageData = array_merge($genericData, $specificData);

header('Content-Type: application/json');
echo json_encode($pageData);