All frames and detected objects are indexed using inception Pool3 features, which serves as a General purpose indexer. So yes you can search for arbitrary objects such as a blue car or a long or a particular "scene", at the same time when definition of "similarity" is more object-specific/fine-grained (such as in case of face) you can use a custom network (such as facenet for faces) to generate the embedding/indexing vector.

To summarize yes we provide two indexers out of the box a general purpose inception v3 and a facenet. We plan to add more indexers soon, e.g. trained on Open Images or other domain specific dataset.