 Because of the nature of the matters heard before it, court hearings may need to take place at any time of day or night, weekdays or weekends; thus, at least one judge must be "on call" at all times to hear evidence and decide whether or not to issue a warrant.A heavily redacted version of a 2008 appeal by Yahoo!of an order issued with respect to NSA's PRISM program had been published for the edification of other potential appellants.