@Override
    protected Provider buildChain(DeployState deployState, TreeConfigProducer<AnyConfigProducer> ancestor, Element providerElement,
                                  ChainSpecification specWithoutInnerComponents) {

        ProviderReader providerReader = new ProviderReader(providerElement);
        FederationOptions federationOptions = readFederationOptions(providerElement);

        Provider provider = buildProvider(specWithoutInnerComponents, providerReader, federationOptions);

        Collection<Source> sources = buildSources(deployState, ancestor, providerElement);
        addSources(provider, sources);

        return provider;
    }
Retrieves all possible provider specific parameters
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/chains/search/DomProviderBuilder.java