return project.getConfigurations().stream()
            .map(ConfigurationInternal.class::cast)
            .filter(c -> c.isDeclarableByExtension())
            .map(ConfigurationDetails::of);
    }

        Set<Configuration> filteredConfigurations = new HashSet<>();
        for (Configuration configuration : Objects.requireNonNull(getTaskConfigurations())) {
            if (((ConfigurationInternal)configuration).isDeclarableByExtension()) {
                filteredConfigurations.add(configuration);
            }
        }
        return filteredConfigurations;
    }

    @Internal