class TrustyCms::ExtensionPath

are being passed around as symbols.
Note that at this stage, in line with the usage of config.extensions = [], the extension names

If a configured extension has not been found during initialization, a LoadError will be thrown here.
Returns a list of path objects for all the enabled extensions in the configured order.

def enabled
  enabled_extensions = TrustyCms::Application.config.enabled_extensions
  @@known_paths.values_at(*enabled_extensions).compact
end