How to expand/un-collapse the specific panel of FAQ (Bootstrap) via URL

You can get URL Hash with window.location.hash and add in class to toggle via getElementById(hash)

Try the following code.

if(window.location.hash)
{
    // hash found
    var hash = window.location.hash.substring(1); //Puts hash in variable, and removes the # character
    alert (hash);
    document.getElementById(hash).classList.toggle('in');
}