The exporter is the piece of the indexer that exports data from the blockchain binary/node to the database. As the exporter is exporting, it also transforms data, updates the cache, and triggers webhooks based on state changes. More information on each of these can be found in their respective docs:
The exporter transforms state change events using the configured transformers. See the transformers docs for more information about transformations and why they are necessary.
The exporter fires webhooks when it detects a state change event that matches a configured webhook. See the webhooks docs for more information about webhooks and how they work.
The exporter invalidates the cache when it detects a state change event that invalidates a computation. See the cache docs for more information about the cache.