if you read the architecture spec of indra you will see that it uses the same source-routed onion layered encryption/forwarding scheme as lightning uses, except for with traffic

there is actually a "message" protocol in lightning nodes, this project was intended to be something like popping that out to the front and putting teh LN in the back as the way to limit spam and incentivise node runners

ecash is a client/server tech that was invented in 1983 by David Chaum, and while it has its uses, anonymity is NOT one of them, and i have had multiple harsh interactions with Calle about this, and he conceded i was right, ultimately mints know who mints and who redeems

the Indra protocol enables you to use Keysend or AMP payments (AMP is a multi path, failure resistant variant of route selection) that enable you to load your accounts anonymously with indra nodes without them knowing who you are, and you can do this with LN, you can't do this with ecash, or at least, the mint is a weak link in this process, lightning onion routing prevents the correlation in origin (it doesn't hide timing though, but this is the same in Tor as well)