Right now, the following observers cannot be declared on an extension:

void first(@Observes Object foo,  Bar bar) {
}
void second(@Observes @Foo Object foo,  Bar bar) {
}

whereas this one is allowed:

void third(@Observes Foo foo,  Bar bar) {
}

Note that the first observer would be notified even for container lifecycle events and so it's considered a container lifecycle event observer. However, the second observer is incorrectly considered a container lifecycle event observer too.

Observers.isContainerLifecycleObserverMethod() should return false for an observer with observed type java.lang.Object and a qualifier other than @Any.

Note that all the above observers are defined as non-portable in the spec. The problem is that extensions can communicate using events and so the required beans may be not discovered/available yet.

However, I think Weld should be consistent here. If third is allowed, the second should be allowed too.