The Saito Archive is a default module that provides nodes with the ability to save transactions in a local database for fast-retrieval, and to serve these same transactions to peers on the network when requested. It is an important part of how the Saito Network supports an browser-to-browser mesh network.
Common uses of the Archive module are to save the transactions that are related to network-supported NFTs. Modules like Saito Redsquare use the Archive module to cache relevant tweets, and serve them to friends when they join the network.
Most implementations of Saito bundle the Saito Archive by default with all applications. If you do not with to save transactions in your browser and serve them to friends, you can disable the Archive module through standard Account settings.