Avalanche is a new consensus algorithm that was introduced in 2018. There is an active proposal to use it in Bitcoin Cash to enable nodes and miners to come to a pre-consensus on the set of valid transactions before they are included in a block. If used this way, it would give Bitcoin Cash the equivalent of nearly instantaneous confirmations while improving mempool synchronization and reducing the financial incentive to 51% attack.
This website is a proof-of-concept of avalanche pre-consensus. There are avalanche-capable nodes on the Bitcoin Cash mainnet running the avalanche protocol. Whenever a transaction is finalized, that is when it reaches the point at which it can no longer be reversed by a double spend, it is added to the list above. As you can see, at present most transactions become irreversible after just a couple seconds. To take this from proof-of-concept to an actual consensus rule will require lots of testing, experimentation, data collection, code review, and softfork activation rules. If you are interested in contributing please get in touch.