/usr/local/etc is a common pattern, though. So maybe I would add that /usr/local is a special case of /usr for locally built* stuff, with sub-nodes imitating t

/usr/local/etc is a common pattern, though. So maybe I would add that /usr/local is a special case of /usr for locally built* stuff, with sub-nodes imitating the corresponding nodes in /. * Not always locally built, though. *BSDs put binary packages there too.