Re: modify sign-in URL
XC5 has multiple ways of calling a template.
1. Class calls it through getDefaultTemplate method - in this case decorate the class and replace the template path/name with your own.
2. Another template calls it directly with twig "include" - in this case you need to replace the parent template so you can change the call.
3. The template in question has @ListChild directive that tells it to show within whatever list - in this case use moveTemplatesInList method in your module Main.php class to delete the original template from the list and add your own