The deleted code was a broken method of generating camera geometry information from a paf file. The code and paf file are gone because that is deprecated. It can be resurrected from git history should Subaru decide it wants to generate its camera geometry information from a text file, instead of directly modifying the generated results.
RFC-192 for more information. Permission was given on the HipChat in the HSC Synchronization room. Given that this was removing broken code, nobody seemed to feel that an RFC or wider review was necessary.
Note that I took a different route for CFHT because the generating code was less broken (it ran but gave slightly incorrect results): the outdated code is marked as deprecated and prints a warning if used. I figured the folks maintaining obs_cfht could figure out what to do next based on the outcome of