LNM is really killing it with these newsletters. I wonder what time commitment they're giving to them ... It's clearly worth it from a marketing angle - I wouldn't be aware of them otherwise.

For LN onion routing, I find a visual approach to understanding it a bit easier. This video by Rene is quite short (10m) and does an excellent job covering both HTLCs and onion routing: https://www.youtube.com/watch?v=toarjBSPFqI.