I still don't think you adequately explained why that would matter. To reiterate the question OP asked: what updates does it need that it hasn't been getting? It isn't as if one would expect a "put X stuff in y location" document to need maintenance.
The FHS 3.0 doesn’t reflect current practices, such as the /usr merge, nor the /sys directory. There’s other ways it’s either no longer followed or missing developments from the last 10 years.
