This is very exciting news, I don't know if any of you still remember the Ark project's homepage (which seems to be offline at the moment, an archived version can be viewed at
the Wayback Machine or maybe try
https://arkdev.info), but it was billed as a second layer for Bitcoin, similar to Lightning Network but it doesn't use Lightning Network at all.
Basically by storing the UTXO set, users can send and receive payments without downloading the blockchain.
Now there are two repos that have been published on Github in the last 24 hours: a monorepo, for running Ark (in Golang), I think, and clArk, an Ark implementation in Rust.
You can find both of them inside the organization at
https://github.com/ark-network .