Where is Cookie['Drupal_visitor_autologout_login'] set?

Have a look at the autologout.js line 158. https://www.php.net/manual/en/language.variables.external.php

I think this is duplicated to 3308456 ✨ Autologout cookie is not secure Needs review

There are two places where the cookie gets set.

The first one happens in the autologout.module, when the user logs in. This line in the code.

The second is in the autologout.js, when the user extends the logout timer in the dialog. This line in the code.