Coverage of config parameter/value storage for app and core developers

[joshtrichards]

I think this would be some useful information to compile for app as well as core developers.

Not just solely for documentation purposes, but from a systems design perspective.

Potential content coverage (eventually, not necessarily initially):

• When to use each type (other than user):
  • config/config.php
    • i.e. when required for (during) initial installation (but not post-install configuration matters); when required to be available to the built-in Updater
  • system config values
  • system core config values
  • app config values
  • user-level values (i.e. specific to admins)
• Special policies (if any)
  • re: config/config.php
    • i.e. usage by non-shipped apps
  • Exceptions
    • Grandfathering (For Now)
    • Grandfathering (For Reasons)
• How-to:
  • Document
  • Deprecate
  • Migrate

That said, currently I'd probably label this:

• nice to have
• future tech debt

So still probably low priority (unless someone just finds themselves really compelled to jump on it of course).