[1] It is intended to enable fast transactions among participating nodes (independently run members of the network) and has been proposed as a solution to the bitcoin scalability problem.
Despite initial enthusiasm for the Lightning Network, reports on social media of failed transactions, security vulnerabilities, and over-complication lead to a decline in interest.
Transacting parties use the Lightning Network by opening a payment channel and transferring (committing) funds to the relevant layer-1 blockchain (e.g. bitcoin) under a smart contract.
The parties then make any number of off-chain Lightning Network transactions that update the tentative distribution of the channel's funds, without broadcasting to the blockchain.
[6] To initiate closing, one node first broadcasts the current state of the transaction record to the network, including a proposed settlement, a distribution of the committed funds.
The other option is uncooperative closure, for example if one node has dropped from the network, or if it is broadcasting an incorrect (possibly fraudulent) transaction state.