This build is mentioned in PX01168, along with 58 and 60. This build was probably intended for release as the Final Beta, but due to bugs it was recompiled several times, thus build 61d became the official Final Beta. It was compiled someday in early December 1991. Nothing else is known about it.
It is also mentioned in PX01251, alongside 71, 101 and RCs 1-3.
It is also mentioned in TERMINAL.EXE in early Chicago builds.
