I'm confused. Supposedly the lightning node is in the browser, but according to my interpretation of the source code, the browser contains a front-end app which communicates with a back-end; Hence the node is actually running custodially on a server. I'm assuming the front-end signs the transactions, which is what makes it noncustodial, but I wasn't able to find that part of the code.

This also implies that multiple users use the same node, just different channels on that same node.

I'm quite interested in how this actually works.