Why are CPACK_* variables documented in two different places?

Hey, Brad—can you comment on this advice I gave four years ago? A commenter on SO asked a few days ago whether this behavior was documented anywhere—specifically, the behavior of passing through all variables with names that start with CPACK_, but also: creating local copies of these variables that have the CPACK_ prefix removed[?] (Full disclosure: I’m assuming it does the latter—or did four years ago—based on my SO answer. But I’ve not used CPack in awhile, and I may be misremembering the details).