As indicated on the docket, the Supreme Court granted permission for Petitioner to file an over-length Opening Brief in Brinker Restaurant v. Superior Court. Sources indicate that the Opening Brief was in the neighborhood of 135 pages, so "over-length" may not truly communicate the magnitude of the Brief.
By all rights, between that Opening Brief and the Opposition Brief, there should be nothing left for amicus filers to discuss. In theory, Amicus Briefs should not repeat arguments advanced in the briefing by the parties. In practice, this rule isn't just tested, it is abused. The Proposition 64 briefing, in particular, took great liberties. But the Supreme Court has appeared tolerant on this point, at least as indicated by its liberal granting of permission to file Amicus Briefs. Of course, there is no way of knowing whether such Briefs receive any meaningful consideration if they are duplicative of the parties' Briefs. I assume the "me too" briefs are primarily intended to exert some measure of pressure on the decision, but no one would ever admit as much.