This build is mentioned in Microsoft Antitrust docs, namely document PX07614. It was originally believed to be a typo of build 34e, but it was released on BA FTP in February 2014. It's also mentioned in build 61d's README file.
The build calls itself "Beta Release 2". The antitrust docs and the README from build 61d also confirm this build is Beta 2. There could be a Japanese version of this build as well, as PX01171 suggests.
