The video contains a demonstration of using a runtime field to fix errors in the indexed data. We intentionally index documents with some errors, and then use a runtime field to shadow the indexed field. The demonstration shows how a user querying the data or creating a visualization in Kibana Lens will see the correct information, which is calculated in the runtime field. This scenario allows for immediate fixing of errors in the indexed data by shadowing them with runtime fields (instead of reindexing). Runtime field is the name given to the implementation of schema on read in Elasticsearch.