The “standard” doesn’t tell you what directory structure to use inside /etc to group related config files. The “standard” doesn’t tell you where an HTTP server should serve its files. Everyone just does their own thing which makes upstream docs incorrect and useless for newcomers.
The FHS, does actually answer both of of those questions. Files inside /etc/ should be grouped in subdirectories[0] andd the HTTP server should serve user-specified website files from /srv[1] and normal distro-provided files (such as the apache test page) from /var[2].
[0]: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s07.htm...
[1]: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s17.htm...
[2]: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05.html#p...
I’ve never seen that in my life, but I’m sure someone does that. This is one of those cases where the people who follow the standard are increasing fragmentation