WARNING: LNURL must be used over https or TOR
LNURL is a range of lightning-network standards that allow us to use lightning-network differently. An LNURL-pay is a link that wallets use to fetch an invoice from a server on-demand. The link or QR code is fixed, but each time it is read by a compatible wallet a new QR code is issued by the service. It can be used to activate machines without them having to maintain an electronic screen to generate and show invoices locally, or to sell any predefined good or service automatically.

Exploring LNURL and finding use cases, is really helping inform lightning protocol development, rather than the protocol dictating how lightning-network should be engaged with.