You can think of credentials as whatever you put on the table when someone asks, how do I know about you? A degree, a licence, a list of jobs, a pass on a lanyard, a password at a sign-in screen — different objects, one job. Each of them stands in for you and answers for you, so the person deciding does not have to take your word.
credentials 可以想成：有人問你「我憑什麼相信你」的時候，你放到桌上的那些東西。學位、證照、做過的案子、掛在脖子上的證件、登入畫面上那組帳密——東西長得不一樣，但做的事情是同一件。它們代替你開口，讓對方不必只靠你的一句話來決定。
登入就可以看每一支怎麼連回核心畫面。