neutrino-elements uses Compact Block Filter (BIP0158) to implement a light client for elements-based networks.
Two services are provided, they can work independantly:
NodeService is a full node maintaining an up-to-date state of the block headers + compact filters. The NodeService writes down headers and filters in repositories.
ScannerService uses filters and headers repositories to handle ScanRequest which aims to know if an outpoint (identified by its script) is spent or not.