Comment by godelski

It's also worth noting that this is a fairly standard pattern in /etc

  /
  | etc
  | | fail2ban
  | | | action.d
  | | | fail2band.d
  | | | filter.d
  | | | jail.d
  | | ssh
  | | | ssh_config
  | | | sshd_config
  | | systemd
  | | | network   # network wide context
  | | | nspawn    # containers
  | | | system    # system wide context
  | | | user      # user wide context
  

Personally I like it more than

  /
  | etc
  | | cron.d
  | | cron.daily
  | | cron.hourly
  | | cron.monthly
  | | cron.weekly
  | | ...
  | | firewall
  | | firewalld

Keeps things less cluttered. Hierarchical categorization is >> than lateral