What is the meaning of such an authorization and how to replace it with the standard (local) authorization on the site?
Maybe this will help? - OAuth .
OAuth is an open authorization protocol that allows a third party to provide limited access to the user's protected resources without having to transfer her login and password to a third party. For example, a user who wants to provide a social network service with access to the contact book of his email account does not have to give his password from the network to the network. Instead, it is authorized directly in the mail service, which (with the permission of the user or the service administrator) grants the social network service access to the address book.