I wrote about Liquid a long time. It basically a bitcoin sidechain dedicated for exchange use. It built on a federated sidechain aka the funds are held by a group of people to peg the coin in the sidechain. It not as decentralized as bitcoin main net but it as close to getting noncustodial. And with drivechains(http://drivechains.org/what-are-drivechains/how-does-it-work/) the federation will be gone!
What this does is when you withdraw from an exchange the exchange to another exchange it uses Liquid which saves your fees and gets confirmed much quicker. Since much Bitcoin traffic is done by exchanges, onchain main net traffic will lessen making fees cheaper for individual users. Learn more about Liquid here: https://bitcoinmagazine.com/articles/blockstreams-liquid-network-high-value-bitcoin-payments-live/
Liquid has 23 partners lined up to serve as Liquid members, namely Altonomy, Atlantic Financial, Bitbank, Bitfinex, Bitmax, BitMEX, Bitso, BTCBOX, BTSE, Bull Exchange, DGroup, Coinone, Crypto Garage, GOPAX (operated by Streami), Korbit, L2B Global, OKCoin, The Rock Trading, SIX Digital Exchange, Unocoin, Xapo, XBTO and Zaif.
Bakkt is rumored to use it as well due to working with Blockstream.
Image source: https://bitcoinmagazine.com/articles/blockstreams-liquid-network-high-value-bitcoin-payments-live/
