Copyright © 2020 by Thomas E. Dickey
Here is the rcs-blame program written by Michael Chapman.
According to the change-log, Michael Chapman wrote blame in 2004, making minor fixes in 2006. This was on SourceForge; however the project page went away some time in 2018.
I happened to notice this program because I was looking for programs to compare with rcshist. Debian had a package; I installed it on my Debian 6 in 2012.
I noticed that the project page was defunct because it broke the FreeBSD port. Not only the SourceForge page was defunct, but the Internet Archive had no copies of the source. I located the source on ftp.sunet.se.
Like the rcshist tool, this is used for analyzing changes using the RCS history of a file:
None, yet (2020/01/25).
I will probably disentangle it from automake, and fix compiler warnings.