Searches, Briefs, Posts and Brain come with Premium, for a site you have claimed.
Posts is part of Premium
Briefs for posts on X and LinkedIn about each page a brief became, once a read finds it live: the point, a fact read from the site that carries it, the link, its voice, and the room left. mttr writes no post and posts nothing.
It is part of mttr Premium, for a site you have claimed. Sign in to the account that claimed the site, or claim it.