Generally, the configuration container is a

NamedDomainObjectContainer

like any other

So you could e. g. do

_configurations_.whenObjectAdded

but iirc that completely disables laziness as then all need to be realized to trigger that hook.

So still the question, what is the use-case, maybe there is a better way someone can come up with.

project.pluginManager.withPlugin("java") {
      onApi("apiElements")
      onRuntime("runtimeElements")
    }

etc...

I'm playing cat and mouse with each plugin to know when they register their outgoing configurations

I could probably investigate each plugin and try to understand when those are created and use proper APIs for that but it's a huge pain