The Foreign Intelligence Surveillance Court and the Foreign Intelligence Surveillance Court of Review apply the Foreign Intelligence Surveillance Act, as amended; the USA PATRIOT Act is, AFAIK, largely irrelevant to them.
Their decisions, including the legal reasoning and analysis, are largely themselves classified, and are (like most warrant application procedures) non-assertive, which presents a significant problem of transparency. (Regular warrant application processes, insofar as they support what eventually turns into criminal prosecutions, at least are aimed at feeding into adversarial proceedings which can reject their results, which mitigates the problems stemming from non-adversarial proceedings.)
Their decisions, including the legal reasoning and analysis, are largely themselves classified, and are (like most warrant application procedures) non-assertive, which presents a significant problem of transparency. (Regular warrant application processes, insofar as they support what eventually turns into criminal prosecutions, at least are aimed at feeding into adversarial proceedings which can reject their results, which mitigates the problems stemming from non-adversarial proceedings.)