in theme/src/main/assets/assets/javascripts/groups.js [159:170]
function groupOf(elem) {
const classAttribute = elem.next("dd").find("pre").attr("class");
if (classAttribute) {
const currentClasses = classAttribute.split(' ');
const regex = new RegExp("^group-.*");
const matchingClass = currentClasses.find(cc => regex.test(cc));
if (matchingClass) return matchingClass;
}
// No class found? Then use the tab title
return "group-" + elem.find('a').text().toLowerCase();
}