"In this commit, we add new feature to lncli sendpayment (and the RPC): the ability to send a payment to a destination without first needing to have an invoice. This allows users to start exploring a new set of use cases that benefits from this type of spontaneous payment. The payment can also carry additional application-specific data such as an account ID, API call, etc. This new feature requires the new EOB (extra onion blob parsing) implemented here. The coolest part about this new feature is that it can be used todayin the wild as long as both nodes are updated to this branch!"

https://github.com/lightningnetwork/lnd/pull/2455