This build is mentioned in Microsoft antitrust document PX01251. All release candidate builds in that document (except 71 and 101) are simply referred to as "RCX" and not by their actual build number. A file from build 101 is versioned "3.1.0.101 (RC1)", so the RC1 referred to in that document must be a later build than 101, or at least a recompile of it.
