private Collection<ErrorMessage> asUnmodifiableSearchErrorList(List<com.yahoo.processing.request.ErrorMessage> queryErrors,ErrorMessage resultError) {
        if (queryErrors.isEmpty())
            return List.of(resultError);
        List<ErrorMessage> searchErrors = new ArrayList<>(queryErrors.size() + (resultError != null ? 1 :0) );
        for (com.yahoo.processing.request.ErrorMessage queryError : queryErrors)
            searchErrors.add(ErrorMessage.from(queryError));
        if (resultError != null)
            searchErrors.add(resultError);
        return List.copyOf(searchErrors);
    }
Picks apart the result and feeds it to the other methods.
container-search/src/main/java/com/yahoo/search/rendering/SectionedRenderer.java