Why should this be included in the repository? Unbound is a blazing fast validating, recursive, and caching DNS server. It is quite useful for enforcing DNSSEC and caching DNS queries. Best used in conjunction with DNSCrypt.
Is it Open Source (yes/no): Yes, BSD licence.
Link to source tarball/zip file: https://www.unbound.net/downloads/unbound-1.5.10.tar.gz
Notes: Have to ensure the port dnscrypt uses (in its socket file) is forwarded in /etc/unbound.conf with the option forward-addr: 127.0.0.1@53 should you include a standard unbound.conf file, in which case I recommend reading this article https://wiki.installgentoo.com/index.php/Unbound