Unwatch all repositories of an organization

gistfile1.txt

(function () {
  const org = 'ORG'
  
  const nodes = document.querySelectorAll('.Box-row');
  const rows = [ ...nodes ];
  const orgRows = rows.filter((e) => e.innerText.startsWith(` ${org}/`));
  const orgUnsubButtons = orgRows.map(row => row.querySelector('button.select-menu-item[value="included'));
  
  orgUnsubButtons.forEach(button => console.log(button.click()));
    
})();

Great! I only had to remove the leading space before ${org}/ to make it work for me.