A few rules to make it consistent:

• The routes should be prefixed (/feed/, /api/, /help/ etc...)
• The main routing file goes to /config/routing/<prefix>.yml and if it has to be split the other files goes to /config/routing/<prefix>/<name>.yml
• The services should be prefixed by <prefix>.
• The main service file goes to /config/container/<prefix>.yml and if it has to be split the other files goes to /config/container/<prefix>/<name>.yml
• The controllers goes to /phpbb/<prefix>/controller/<name>.php