...Download verification is optional but highly recommended. Performing the verification steps here ensures that you have not downloaded an unexpected or tampered version of Bitcoin, which may result in loss of funds. Experienced users who don't mind performing additional steps can take advantage of Bitcoin Core's reproducible builds and the signed checksums generated by contributors who perform those builds.
This a mirror of the official Bitcoin-ABC repository
...It uses peer-to-peer technology to operate with no central authority: managing transactions and issuing money are carried out collectively by the network. eCash is a descendant of Bitcoin. Bitcoin ABC is the name of open-source software which enables the use of eCash. It is a fork of the Bitcoin Core software project.
...A Proof of Stake consensus system which is optimized for Qtum's contract model. Any user can stake and help to secure the network. There is no voting, master nodes, or minimum amount required. There have been transactions as small as 2 Qtum that have created blocks in the past. Staking from smart contracts is under development.
...Metrocoin uses peer-to-peer technology to operate with no central authority: managing transactions and issuing money are carried out collectively by the network. Metrocoin is also the name of the open source software which enables the use of this currency.