Its super new and not well documented. Maybe the site can help: https://l2.technology/sensei
Basically, it uses a single bitcoind connection and a single channel graph and gossip stream to feed multiple lightning nodes. This saves significantly on bandwith and storage with minimal configuration. The UI let's you manage all your nodes from a single admin area. It should be available on Umbrel, etc. in the next few months.
Oh i see, that's interesting that it shares the channel graph and the gossip stream. I am building a project that requires multiple core lightning nodes for redundancy in case one goes down, but maybe this is a path to explore. Thanks for the explanation!