Manually Set an Item as Active Any item can be set to active to indicate that the page is anchored to the respective section. Demo
{% include '@bolt-components-toc/toc.twig' with {
  items: [
      text: 'Section One',
      url: '#section-one',
      text: 'Section Two',
      url: '#section-two',
      active: true,
      text: 'Section Three',
      url: '#section-three',
} only %}
  <bolt-toc-item url="#section-one">
    Section One
  <bolt-toc-item url="#section-two" active>
    Section Two
  <bolt-toc-item url="#section-three">
    Section Three