Thanks!
So, in RGB, UTXOs are used to anchor tokens, and so when you transfer a token, you need to provide a UTXO that has been obfuscated by the receiver using a blinding factor that only they know, and they will provide the blinding factor to the recipient should they ever choose to spend their own tokens. For the high-level workflow, I recommend reading this: https://github.com/LNP-BP/nodes/blob/master/contrib/demo-rgb.sh
Discussion
I assumed that there was something in the invoice to put a state commitment into the utxo but didnt know how to wire it all up. This looks super helpful