"Briefed" would usually mean 'briefly described' or summarised. Sometimes we say 'he briefed me about the situation' meaning he gave me a brief summary/description of the situation. Occasionally this can be used as a verb.

Hi Natasha, I am not sure of the context but usually "briefed" mentioned like this could mean outlined, that provide information or written there. "Please read the terms that provide information / written there inclusive xxx" Briefed is a verb. To brief someone is to provide information or instructions for them. For example, you could say that I am briefing you on the use of the word brief. Hope some of that is helpful, Alice

When someone is briefed about something, they are informed about a subject. It is a past tense verb. Usually it is used in official circumstances. "The Governor was briefed about the coronavirus."