Howard Oakley comes to the rescue once again: Ventura volume layout – The Eclectic Light Company
Actually, not all of /System/Library is firm linked to the Data volume. Only some subfolders of /System/Library (as well as the entirety of /Library) are “firm linked” to the Data volume. Note that you can always find exactly what’s firm linked from the SSV to the Data volume by reading the file /usr/share/firmlinks (again, thanks to Mr. Oakley).
Nobody said it was.
I’m sorry if I misinterpreted your original statement on /System/Library.
Just about everybody on this thread was discussing or just trying to understand OP intent, which has not become any clearer. For those of us in that camp, let’s not argue amongst ourselves, eh?
I agree. This effort to assist other users in dealing with Apples security idiosyncrasies, and lack of appropriate documentation and tools to address issues with the root Library has taken on a life of its own. Much of it has been with dealing with semantics and technical details that are of little interest to the average user. My sole goals was the share my experiences and provide the average user a warn of an issue that could destroy their data without warning and provide a hopefully simpler alternative to repair the root Library if it does get corrupted. Instead it has seemly morphed into the technical equivalent among some posters as a pissing contest.
For these reasons I have decided that this will be my last comment on this thread and I would encourage the Tidbits Monitor of this site to close this thread.
For folks who have questions about what is going on with their Macs (models and systems from 2016 to present in particular), I strongly recommend (not necessarily in this order):
a) asking specific questions here on TidBITS
b) using Apple Help, particularly if your machine is still under warranty (i.e. genius bar, if that still exists)
c) researching Howard Oakley’s repository of knowledge, located at
He does start with Ventura, working his way back (he even mentions macOS 14!).